Guide to AoE Grinding: Class, sets, and skills for optimizing kills

Woodenplank

Introduction

Whether you're trying to speed that new character to level 50, farming hide scraps from habless animals, or simply trying to make a dent in that daunting pool of Champion Points; AoE-grinding - the art of killing very many enemies very fast - is a stable and popular method; as popular and effective in ESO as it is in many other MMOs.
While many guides showcase favourite farming spots - places with a great mob density and/or fast respawn rates - I find that there aren't many guides for setting up your build itself.

So here I'll share personal experience and conjecture on optimizing AoE farming.
I'll also give a personal opinion rating on the game's Classes, sets, and skills, rating by availability, efficiency, and how well they lend themselves to leveling.

####################### CHAMPION POINTS #######################
If you have yet to muster your first level 50 Character, you can skip this section.
For people making secondary++ characters, you can select Champion Points starting from level 1 to immensely speed along the AoE grinding process.

Warrior/Red

• Siphoning Spells - Restore 300 Magicka whenever you kill an enemy
  Sustain made easy. As long as you keep killing it's (almost) impossible to run out of Magicka.
• Bloody Renewal - Restore 300 Stamina whenever you kill an enemy
  Stamina version of the above. Do note that some content/builds may want to slot both of these, but you typically only need the one corresponding to your main AoE spamable.
• Thrill of the Hunt - Gain Major Expedition for 3 seconds whenever you kill an enemy.
  Greatly decreases time between separate enemy pulls by giving you a free 30% movement speed increase. This should always be slotted if possible.
• Celerity - Increases movement speed by 10%
  Not as large a bonus as Thrill of the Hunt, but it provides a consistent speed boost. Furthermore, it is an 'unnamed buff' meaning that if you have another source of Major Expedition, there's no reason to slot Thrill, and this CP becomes the choice for mobility.
  If you have the CP slots to spare, you could also slot both.
• Boundless Vitality - Adds 1400 maximum health
  For builds that lack durability. Particularly useful if you're running Thrassian Stranglers.

Mage/Blue

• Biting Aura - +6% Area of Effect Damage dealt
  Obviously you want this. The whole deal is to burst down groups of enemies quickly.
• Master-at-Arms - +6% Direct Damage dealt
  Since most of our AoE damage should be coming from direct bursts (rather than waiting for DoTs to kill enemies) this is another solid pick.
• Wrathful Strikes - 205 Weapon and Spell Damage to your damaging abilities
  Solid, dependable damage boost.
• Fighting Finesse - Increases Critical Damage and Healing by 8%
  Another generic damage boost, but mileage may vary based on your crit chance.
• Reaving Blows - Restore health equal to 7% of Direct Damage dealt
  If your build lacks staying power or you find yourself having to cast heals instead of damage abilities, then this CP can save you. With this, anyone can feel like a Magicka Jabplar!
• Exploiter - Increases your damage against Off-balance targets by 10%
  AoE off-balance is sort of rare, but if you have it, this is the greatest single CP damage bonus available. Necromancers with Ruinous Scythe should consider.

###################### SKILLS AND ABILITIES ######################

Arcanist - A

Fatecarver (BOOK BEAM OF DOOM): Already unlocked at rank 4 of Herald of the Tome, it is the one and only source of area damage you'll ever need.
The tooltip on this thing is massive, and the AoE quite generous, even if only in the forward direction. There's even a morph to include a damage-shield on yourself, if you need the survivability.
Did I mention that the preceding ability - Runeblades - can be used to generate Crux, and also has an AoE morph? Well it can and it does.

Later on in the Herald of the Tome line we also find Tome-Bearer's Inspiration which, even if you don't actively cast it, provides the valuable Major Sorcery/Brutality buff even while slotted on the backbar.

Now I don't mean to say that there's anything wrong with the rest of the Arcanist's kit, but frankly the abilities mentioned above are so overwhelmingly "the only thing you'll need" that I won't bother describing the rest.

Dragonknight - C

Obligatory "nerf DK please."

With that out of the way, AoE grinding is most definitely one of the weaker facets of Dragonknights.
Standard of Might and Eruption are a couple of the strongest AoE abilities in the game, but require your target to be standing in the same area for a very long time. Much longer than you would (want to) when farming mobs.
Burning Talons is another AoE ability which suffers from having half its damage tied into a DoT - and that's only after morphing it!
Inhale is yet another decent ability on paper; area damage and self-healing! But it is the very last ability unlocked in Draconic Power and doesn't lend itself to spamming, given it's 2.5 seconds detonation timer.

Fiery Breath, going into Noxious Breath is a decent ability. It has some upfront, direct damage, and is one of the few sources of AoE Major Breach in the game.
On the other hand most of its damage is tied into a lengthy DoT effect, and it is only unlocked halfway through the Ardent Flame tree - with the DK having to rely on the two previous abilities (both single target) to garner Skill-Line XP first.

While the whole DoT pressure, survivability, and Molten Whip bursting makes DKs formidable in PVP, it doesn't lend itself very well to bursting down great swaths of lower health mobs.

Nightblade - B+

The shining glory of Nightblade AoE farming, Drain Power, is sadly unlocked only at the very end of the Siphoning Skill-Line.
Once unlocked, of course, it's a powerhouse. Sap Essence provides Major Sorcery/Brutality, and has 360° degree area damage with commensurate self-healing. And if you're good on sustain, Power Extraction can instead yield Minor Courage as well, for some extra OOMPH!

But this begs the question: for a leveling Nightblade, what do you use until Siphoning is up to lvl 42? And the options honestly aren't great.
Sure; Teleport Strike has an AoE morph, but it's rather awkward to cast with a lengthy animation, and most of the damage is tied into a DoT.
Twisting Path does area damage, but again takes a good while to deal its full damage --- (It does however remain useful in also providing Major Expedition between pulls).
Leveling Nightblades will typically have to rely on out-of-class AoEs until later levels.

P.s. For slotting Soul Harvest you generate a nice dose of Ultimate for every kill.
I have not tested this myself, but I think that a Nightblade (potentially with Dead-Water's Guile) could keep a good stacking of Balorgh's set proc up with almost 100% up-time.

Necromancer - B-

Certainly Blastbones is a pretty strong AoE burst (when it works) but will always take at least a few seconds to land, leaving you with an awkward wait between each cast, having to be filled with other AoE abilities.

Boneyard - the third ability in the Grave Lord line - suffers from two morphs that would both be good for AoE grinding, but allowing only one. And while the area-effect Major Breach of Unnerving Boneyard is tempting, being allowed to use your own GraveRobber synergy with Avid Boneyard is too good.
It is one hel- Oblivion (??) of a synergy though: a powerful AoE burst and self-heal. Being a synergy, however, it is bound by internal cooldowns.

The Scythe Ability and its morphs (particularly Ruinous Scythe) are strong options. However, they suffer from a steep cost and a frontal cone only targeting.
With that being said, Ruinous Scythe proccing both Hemorrhaging and Off-balance on top of dealing direct damage makes it an excellent source of damage.

And while this song has been sung a million times... I must point out Necromancers do lack several important buffs. Namely there's no Major Sorcery/Brutality so you'll have to foray into non-Class skill-lines to find a source.
[/spoiler

Sorcerer - C

Honestly I find that Critical Surge and Hurricane are pretty much the only good options. Hurricane - while it does need time to ramp up its damage, is unlocked very early in the Storm Calling skill-line and provides both Major Resolve (for added tankiness) and Minor Expedition, allowing you to close distance between mob packs much faster.
Critical Surge is significantly later in the Storm Calling line, but the combination of Major Sorcery/Brutality with an automatic self-healing is immense.

Mage's Fury has strong AoE burst, but it's an execute ability, such that you'll have to bring your target down below 25% health with some other ability first.
With that being said, it can help to start a "chain reaction" sort of thing.

One way or another, you'll want to look outside of the Sorcerer class for your AoE spamable.

Templar - A

JABS! Jab-jab-jab-jab-jab-jab-jab!
The first and foremost ability of the Aedric Spear line, this is a godsend for AoE grinding. Your choice of morph will either afford you Major Sorcery/Brutality (the earliest possible source in the game, short of chugging potions at level 1) or a damage-scaled self-healing spamable.
Depending on the rest of your setup, the Stamina morph, Biting Jabs, is the superior damage source, dealing more off-main target damage and providing a damage buff.

Later on, the Aedric Spear line also houses Spear Shards (Blazing Spear) which leaves an area burning with magic damage, but with a surprising amount of upfront direct damage. It's long range also makes it an excellent way to aggro additional mob packs.
Speaking of Aedric Spear... Radial Sweep (and morphs) has the honor of being the cheapest AoE damage ultimate in the game, allowing you to use it on every other mob pack essentially.

In the Templar's other skill lines we find: a level 1 source of Major Prophecy/Savagery (Dawn's Wrath: Sunfire), and AoE aura that further enhances your Class skill damage (Dawn's Wrath: Solar Barrage), and a free post-battle self-heal and stamina restore (Restoring Light: Repentance).
Maybe it's just bias talking, but Templars are honestly my favourite Class for AoE grinds.

Warden - undecided?

I'm sorry to say that I simply don't have enough experience to offer advice on this. I never really took a fancy to playing Warden, and the one character I did make and level up used Alik'r Dolmens, and has been kept as a banker ever since.
And while I can certainly imagine that abilities like Deep Fissure, with its area damage, Minor- and Major Breach would excellent tools, I don't like to advise on things outside of personal experience, so I'll leave it to someone else.

General Availability Skills

Critical Charge - Two Handed - B+
Once morphed to Stampede this ability because an Area of effect burst with a strong following Damage over Time effect. It also helps close the gap to mobs, speeding between packs of enemies all the faster.
The instant damage portion isn't quite strong enough to make it a good spamable, but it's a worthy addition. It is also the second ability unlocked in the Two Handed skill-line, making it easy to acquire.
P.S. Also functions as a proc condition for Maelstrom Two Handed, which can make a great damage addition.

Cleave - Two Handed - A
It may not be the highest damage AoE spamable, and it only hits targets in front of you, but it grants a commensurate damage shield for every target hit, allowing you to cover all your survivability needs by aggressively swinging away.
The shield only grows larger by using the Brawler morph, or you could add bleed damage with the Carve morph.
Either way, it's a strong, dependable direct damage spam. When utilized with the DSA Master's Two Handed weapon, it gains a sizeable damage buff with every additional target hit.

Reverse Slash - Two Handed - C+
Once morphed to Reverse Slice this will deal damage around the main target as well. So while it's a relatively weak spamable up front, targeting a low-health enemy will deal the Execute-scaled damage to all nearby enemies; even those at full health.

Whirlwind - Dual Wield - B+
Either morph will do, but the higher damage of Whirling Blades will typically be best.
I do not rate this higher because, despite its high damage, it also has a steep cost and can be hard to sustain at lower levels. Furthermore, it is only unlocked ~halfway through the Dual-Wielding skill line, forcing you into other options for starting levels.

Blade Cloak - Dual Wield - C+
Not dealing direct damage, you can't spam this for quick kills. It is, however, a solid addition to your damage. The Major Evasion may slightly aid your survivability.
Deadly Cloak offers more damage while Quick Cloak offers longer duration and a source of Major Expedition when running between mob packs.
It is, however, one of the last Dual-Wield abilities unlocked.

Wall of Elements - Destruction Staff - B
The Unstable morph deals decent damage, even as a spamable, when wielding a Flame staff, and it's available fairly quickly as the second skill in the skill-line.
It is, of course, mostly a DoT, but the damage is high enough and the cost low enough to make it serviceable.

Impulse - Destruction Staff - B+
This is, of course, the main AoE spamable of the Destruction line, with a price and burst damage to match. I would probably recommend the Lightning variety, since it deals up to 30% more damage when striking multiple targets. Also keep in mind that Lightning Staves can passively increase Direct Damage done by 12%.
The Pulsar morph applies Minor Mangle, reducing enemy (max) hit points by 10%, putting you off to a great start in every pull.
The main detraction from this ability is being the final unlock in the Destruction skill-line, meaning that leveling characters could/should have already settled on an AoE spamable before accumulating enough experience to unlock this ability.

Volley - Bow - D+
It does deal a decent amount of damage on a relatively short time (if you pick Arrow Barrage morph), but the smallish area and full 10 seconds actuation time makes it a weak option.

Arrow Spray - Bow - B+
A fairly high damage ability, but unlocked rather late in the skill-line. Acid-Spray gives it double damage with a 5 second DoT, which doesn't do much for the direct spam, but adds up.
It does have the downside of being a conal area, which can lead to some difficulty in targeting when mobs surround you in melee.

Caltrops - Assault - C+
Once morphed to Razor Caltrops this applies Major Breach to all enemies in a large target area.
The only reason I don't rate it higher is that it comes from the Alliance War, which makes it a very awkward unlockable for speed leveling characters.

Magelight - Mages Guild - B
Slotted for Major Prophecy/Savagery. The Inner Light morph also increases max magicka.

Entropy - Mages Guild - C+
Not an AoE skill, and requires Lore Book grinding. But the Degeneration morph gives Major Sorcery/Brutality, so it that's that.

Silver Bolts - Fighter's Guild - B-
Once morphed to Silver Leash useful for chaining in strays or ranged enemies.
Fighter's Guild Passive provides up to 3% bonus Weapon/Spell Damage for slotting.

Expert Hunter - Figther's Guild - B
Slotted for Major Prophecy/Savagery.
Fighter's Guild Passive provides up to 3% bonus Weapon/Spell Damage for slotting.

############################ SETS ############################
These are just my personal favourites and experiences. It is not a comprehensive list, and you may disagree with my ratings.
I may update list later, and will happily hear suggestions.

Mora's Whispers - A+

(1): Up to 1528 Critical Chance
(1): Up to 10% increased Inspiration, Alliance Rank, Alliance skill
(1): Up to 15% monster kill experience
based off how many books of Shalidor's Library have been collected.

Strength/Utility:
Light, shoulder - While it can be difficult to stack enough Lore Books to see real gains, there's simply no replacement for this item. 15% increased XP gains, on top of an automatic Legendary 11% Training Trait. No other single item in the game gives you as much bang for your buck, w.r.t. XP grinding.
On top of that the Critical Rating also corresponds to upwards of 7% increased crit chance, which is a powerful DPS boost in itself.
Due to its shoulder slot, this does bar you from using any Monster set!

Availability:
Mythic - This part is admittedly problematic, and almost drags the item down to just regular A, or even B+ tier. You do need to be CP160 to craft and equip mythic items, and the requirement of collecting Lore Books further complicates its usage.
Consider it late-game optimization for farming CP and the like.

Thrassian Stranglers - A

(1): Killing an enemy grants you a stack of Sload's Call for 1 hour, up to a maximum of 50 stacks. Each stack increases your Weapon and Spell Damage by 23, reduces your Maximum Health by 120, and reduces effectiveness of your damage shields by 1%. Sload's Call is lost if you remove Thrassian Stranglers, go invisible, or crouch.

Strength/Utility:
Gloves, Light - Truly a 'Glass Cannon' Mythic item. Giving 1150 Weapon/Spell Damage at the cost of losing 2760 maximum hit points hones your character into a monster that survives not for any inherent fortitude, but because you'll simply kill anything before it can damage you.
While it may be overkill in many instances, this does free up your build to invest less into damage with other gear.
A word of caution though: the stacks reset whenever you change instance, making it an ungainly item for e.g. Dungeon farming.

Availability:
Mythic - You do need to be CP160 to craft and equip mythic items, meaning that this is really only an option for CP-farming or other late game optimization.

Ring of the Pale Order - B+

(1): Restore 20% of the damage you deal as Health. This value is decreased by 4% per ally you are grouped with. You cannot be healed by anyone but yourself, your pets, or your Companions.

Strength/Utility:
Ring - Essentially all the survivability that any build could need. Restoring 20% of damage dealt back as health means that any Class can now build for 'Glass Cannon' setups where you just attack your way to better health.
The only reason for not ranking this higher is that - truly - you shouldn't need to use a mythic slot to survive AoE farming, in my opinion.

Availability:
Mythic - You do need to be CP160 to craft and equip mythic items, meaning that this is really only an option for CP-farming or other late game optimization.

Heartland Conqueror - A+

(2): Adds 129 Weapon and Spell Damage
(3): Adds 1096 Maximum Magicka
(4): Adds 1096 Maximum Stamina
(5): Increase the effectiveness of your Weapon Traits by 100%. This does not affect Ornate or Intricate traits.

Strength/Utility:
Any type - While the (2)-(4) piece bonuses are rather lacklustre, the (5)-piece is uniquely useful. Combining this with the Training Trait on weapon(s) allows you to squeeze an extra 9% (!) experience out of every kill.
There's simply no other set in the game that provides a bonus like this.

Q: Why not use a setup for more damage = killing faster? Assuming we use Sharpened Trait for 3276 extra pen; ~5% extra damage. With Heartland Conqueror itself, you would double that and get 10% faster kills.
A: But keep in mind that a lot of grinding is not bottlenecked by kill speed, but by the time it takes to pull and stack mobs, or waiting for enemies to spawn like in Blackrose Prison. Furthermore, if you're getting a "carry run," or any other scenario where someone else does the bulk of the damage, then this is the only real set for squeezing more XP out of someone else's killing.

Availability:
Crafted - available in any item slot and armor weight/trait. No downsides, truly.

Night Mother's Gaze - A

(2): Adds 657 Critical Chance
(3): Adds 129 Weapon and Spell Damage
(4): Adds 657 Critical Chance
(5): When you deal Critical Damage you apply Major Breach to the enemy, reducing their Physical and Spell Resistance by 5948 for 4 seconds.

Strength/Utility:
Any type - Available from any level and setup, this is one of the few sources of (potential) AoE Major Breach in the game, the others being locked behind skill lines and morphs.
This makes it an invaluable damage buff for grinding mobs, when you can't rely on anything but your own penetration stats (5948 penetration is roughly 9% extra damage dealt).
Since the buff lasts for 4 seconds, you don't even need a great amount of critical chance to keep it up.

Availability:
Crafted - available in any item slot and armor weight/trait. No downsides, truly.

Pelinal's Wrath - B+

(2): Adds 129 Weapon and Spell Damage
(3): Adds 1487 Offensive Penetration
(4): Adds 129 Weapon and Spell Damage
(5): Whenever you kill an enemy you gain a damage shield that absorbs up to 3876 damage for 10 seconds and a stack of Wrath of Whitestrake for 10 seconds. Each stack of Wrath of Whitestrake grants you 100 Weapon and Spell Damage, but causes you to take 159 Oblivion damage every second, up to 10 stacks. The damage shield scales off the higher of your Weapon or Spell Damage, and the damage scales off your Max Health.

Strength/Utility:
Any type - Assuming you made it through the tooltip reading; I'll add this:

• Each stack of the self-DoT deals 1% of your max. health as Oblivion damage every second.
• The dot stacks up to 10 times and lasts 10 seconds.
• Quick math: The DoT will deal 100% of your max. health as Oblivion damage over its duration if fully stacked.
• Losing 100% of your health is bad for you.

With all that being said, the set also stacks up to 1000 (!) Weapon and Spell Damage. That's an insane amount. That's more than fully stacked Siroria's. That's more than Coral Riptide at min. Stamina. That's almost twice what Camonna Tong gives at most.
Furthermore, the shield strength easily goes above 10k, so as long as you keep killing, you won't have to worry too much about damage from mobs - and the only worry is just outhealing the self-damage.
The set does rely on minimizing time between kills to keep going, but when it works it provides a whole gearup worth of damage.
Plus it also gives you a glowing red aura like you're shrouded in a spray of blood all the time, so that's pretty metal.

Availability:
Crafted - available in any item slot and armor weight/trait. No downsides, truly.

(Perfected) False God's Devotion - B

(2): Adds 657 Critical Chance
(3): Gain Minor Slayer at all times, increasing your damage done to Dungeon, Trial, and Arena Monsters by 5%.
(4): Adds 657 Critical Chance
(5): (Adds 129 Weapon and Spell Damage) & Reduces the cost of your Magicka abilities by 8%. When an enemy you recently damaged dies, you restore 2454 Magicka and gain Major Expedition for 8 seconds, increasing your Movement Speed by 30%. These effects can occur once every second.

Strength/Utility:
Light Armor - The (2)-(4) piece bonuses are solid, but note that Minor Slayer won't work in overland content or delves!
This set gets its rating because of the impressive sustain bonus, and free source of Major Expedition, allowing you to speed from enemy to enemy as you grind out kills.
Using this set allows you to drop the Thrill of the Hunt red Champion Star, and use something else instead.

Availability:
Trial set, Sunspire - It's really only an option for cp160+ characters farming additional Champion points, or somesuch. Not an option for leveling new characters.

Vicious Ophidian - B

(2): Adds 657 Critical Chance
(3): Gain Minor Slayer at all times, increasing your damage done to Dungeon, Trial, and Arena Monsters by 5%.
(4): Adds 657 Critical Chance
(5): Adds 129 Weapon and Spell Damage. Reduces the cost of your Stamina abilities by 8%. When an enemy you recently damaged dies, you restore 2454 Stamina and gain Major Expedition for 8 seconds, increasing your Movement Speed by 30%. These effects can occur once every second.

Strength/Utility:
Medium Armor - This is, quite litterally, just the Stamina and Medium version of (Perfected) False God's Devotion. It has the exact same strengths and caveats.

Availability:
Trial set, Craglorn - It's really only an option for cp160+ characters farming additional Champion points, or somesuch. Not an option for leveling new characters.

Rattlecage - C+

(2): Adds 1206 Maximum Health
(3): Adds 129 Weapon and Spell Damage
(4): Adds 129 Weapon and Spell Damage
(5): Adds 171 Weapon and Spell Damage. Gain Major Brutality and Major Sorcery at all times, increasing Weapon and Spell Damage by 20%.

Strength/Utility:
Heavy Armor - Honestly never considered a particularly strong set. But Major Brusoricery is as close to a mandatory combat buff, so if you have no other way of achieving good uptime, then this is the way.

Availability:
Dungeon, Vaults of Madness - Should probably only be considered for Cp160+ setups, since it drops from an end-level dungeon. You could farm it through dungeon grinding at any level, but not recommended.

Camonna Tong - B

(2): Adds 129 Weapon and Spell Damage
(3): Adds 129 Weapon and Spell Damage
(4): Adds 129 Weapon and Spell Damage
(5): When you kill a monster and gain Experience Points, gain 1 Weapon and Spell Damage for every 50 Experience Point the monster is worth for 30 seconds. This bonus can stack up to a maximum of 540 Weapon and Spell Damage. This item set is not affected by Experience Point boosting effects.

Strength/Utility:
Medium Armor - A massive chunk of Weapon/Spell Damage on a lengthy buff, making it easy to build and maintain.
No particular downsides neither. Only conceivable critique being that Crit Chance and Offensive Penetration would be stronger stats.

Availability:
Overland, Telvanni Peninsula - Being an overland set, it will be very hard to accrue a 5/5 setup on a lower level character, so mostly recommend for cp160+
If you really wanted to use it on a lower level character, the most efficient way might be to learn Training trait on 5 pieces of gear, and the do Sticker Book reconstruction. As long as you've collected the full set, it won't cost you anything (Transmute stones returned upon later deconstruction).

Dead-Water's Guile - C

(2): Adds 129 Weapon and Spell Damage
(3): Adds 1206 Maximum Health
(4): Adds 1096 Maximum Stamina
(5): Adds 129 Weapon and Spell Damage. Whenever you kill an enemy, you gain 15 Ultimate.

Strength/Utility:
Medium Armor - That's a lot of ultimate generation. Mostly recommended for solo-grinding, of course, though you can still land killing blows in group content.
Keep in mind though that you don't/shouldn't need ultimate abilities very often when farming in e.g. Public Dungeons or overland. Things usually die plenty quick.

Availability:
Overland, Murkmire or Blackrose Prison - Being an overland set, it will be very hard to accrue a 5/5 setup on a lower level character, so mostly recommend for cp160+.
That being said; if you happened to be farming Blackrose Prison any way...

Misc:
Dragonknights with Battle Roar passive essentially gain infinite sustain from this set.