I -still- play without a single one, and I've been going since closed beta and early access. Not even highly recommended, IMNSHO.

Storage space is still capped at 170 per character. Don't expect to change.

Great Add-Ons:
Foundry Tactical Combat (FTC) - damage meter, numbers on attribute bars, scrolling combat log - It's good to know how much DPS you're doing, even if you're not pushing for endgame elite status.
Skyshard Hunter - some of the dungeon maps are a little out of date with the changes to delve layouts, but it's still a good way to track whether you've missed any before leaving a zone
S'rendarr (updated for 1.6 version) - two versions of this, one is old and non-functional, the other has been updated by a new dev and provides great windows for tracking buffs and de-buffs.
Wykydd's Framework - A big package of add-ons that improve UI, Mailbox, and other stuff. All of it is toggle-able in game so you keep what you like and turn off what you don't (same goes for FTC above).

Edit: Advanced Filters mentioned above is a must-have. It was out-of-date for a few hours on 1.6 patch day and I was absolutely lost without it.

Thank you for the replies. Advanced Filters seems like one to check out.

Thanks Amsel_McKay. I appreciate your response. Someone mentioned a mini-map add-on. Is there a really good one? I prefer to have one.

Skyshards
Lorebooks
FTC
Srendarr (for buffs and debuffs)
Sous Chef(for keeping track of my Provisoner)
Multicraft(so I don't have to sit there and press a key 30 times when making food or potions)
Master Merchant(Shopkeeper is no longer being maintained)
Destinations(so I can scrape up every bit of xp for my VRs)
LootDrop
No, Thank You (to get rid of annoyances like Trial notifications, delete mail confirmation etc)
Swap Skills (to be able to keep different skill bars handy for pvp, pve, leveling)
GG Frames (so I can move the UI elements where I want them)

If you are going to steal, Fence Info is good to have. I prefer JunkIt to LootDrop-more options. For crafting, Research Buddy 2 to track traits. Anyone mention SousChef? And Harven's Improved Skills lets you see both morphs of a skill at once.

Only ones that are absolutely required are DPS meters if you want to squeeze out every last inch of DPS.

Other than those I would say the rest are not just highly recommended, but are highly, highly, highly recommended.

Research Assistant alone will save you hours and hours of inventory tracking and pen+paper charting when all you want to do is sell stuff you don't need, and keep stuff you need for research.

Tandor wrote: »

It depends on how you approach the game. Personally, I don't see the need for any, but I understand the reasoning of those that do want some. However, I'll never understand the reasoning of those that want the ones that basically show them where everything is - lore books, sky shards, etc. Why play the game if you don't want to play the game?

Because for some playing the game does not include spending time hunting down lorebooks or skyshards.

There might also be certain people with 2 VR 14s and 3 other VR leveled characters who on their 6th play through don't really feel like hunting down everything for the sixth time in a row.

Wykyyd's Suite for sure, and Advanced Counter (to keep track of Ultimate points for longer Overload). The sky shard map is also handy.

Pausekey wrote: »

Because for some playing the game does not include spending time hunting down lorebooks or skyshards.

This 100x.

I usually like hunting down collectibles in Single player games but for an MMO, Skyshards are hard to find and I'd more so like to be able to track which ones I've found and collected and which ones I haven't. Most of them are actually in dungeons or are guarded so I still have to work for them, in that sense.

I'm definitely addons maniac:

• Atlas shows loot from dungeons.
• Combat Cloud displays outgoing and incoming combat events, warnings, notifications, etc. If you like to see your hits and sometimes forget to dodge or interrupt enemies - this addon is good.
• Dustman helps to deal fast with any unwanted items - to mark them as junk, to destroy immediately, etc.
• Harven's Attribute Bars improves existing health/mana/stamina/enemy bars (adds percentage/min-max/none values, for example).
• Harven's Research Timers - I use it instead of Craft Research Timer, but don't like interface
• Harvest Map just warms my soul (wow, how many resources did I find!), but also may be useful for those who don't see resources everywhere
• Item Saver allows to place a little marker on items - so you can remember to not accidentally sell or deconstruct your items. And this items even don't appear in shop list.
• Lootdrop Continued graphically displays informations about all things you looted. Very useful!
• LoreBooks displays on map (and compass if you wish) all books from Shalidor's Library. Some prefer to find them accidentally, but if you don't like such accidents or just want to find a few remain books - this addon is great.
• Lost Treasure shows the treasure map locations on the World Map. The same comment as for LoreBooks But sometime maps are awful and impossible to understand!
• MultiCraft allows to craft as many items as you can create in one click. Useful! But you need to remember, that settings are reset with each item.
• PublicDungeonChampions shows locations of all public dungeons bosses - and marks them as killed. The same comment as for LoreBooks - some prefer to find them on their own
• Rare Fish Tracker displays the rare fish you have caught for fishing achievements in each location.
• Research Assistant marks item if you do not have the trait researched. Simple and cute.
• Show Motifs displays racial motif and armor type for the items in bags and bank.
• SkyShards displays on map (and compass if you wish) all skyshards. The same comment as for LoreBooks
• Slightly Improved Experience Bar displays experience values (current/max, percentage), and does the same for veteran ranks and champion points. You always know how much points is left until you'll up.
• Sorcerer Helper reminds me to summon my minions. Also it can remind about buffs, and alerts when some abilities like Crystal Fragments proc.
• Sous Chef marks Provisioning Ingredients with the next information: which recipes use that ingredient, along with how many of that recipe you can make with your current inventory.
• SpentSkillPoints displays the amount of already spent skill points for each category and skill line. Simple and useful for statistic lovers.
• Zolan's Auto Repair automatically repairs all your damaged gear when you visit a vendor. For lazy players such me.

Out of date addons:

• Achievement Tracker is useful for me to track zone and interesting achievements; unfortunately, it;s old and don't work with Update 6 And author abandoned it.
• Craft Research Timer is useful for crafter maniacs. You needn't to check and remember how many days will this research last. Unfortunately, this addon is out of date, and author visited ESOUI long ago
• Crafting Material Level Display shows the level of crafting materials in the item tooltips and inventory lists. Useful for those who want to keep only high level resources. Out of date, but, maybe, author will update it.
• Luminary - Fish Me reminds where each type of fishing lure should be used and shows alert text when the fish are biting. And sound, sound are the great thing - for example, I prefer to read books till fishing, and want to know when exactly need to press "E". It's working, but out of date and sometimes bugged
• Slightly Improved Attribute Bars allows to shift the mana and stamina bars closer to the health bar, and to move enemy's bar lower or higher. Out of date, and seems the author have abandoned it

must have add-ons for me are
-AdvancedFilters
-CombatCloud
-Destinations
-HarvestMap
-LoreBooks
-MiniMap
-ResearchAssistant
-SousChef
-Srendarr
-TiEmote
-BankManagerRevived

AwesomeGuildStore makes guild traders tolerable.

I'm usually add-on agnostic, but the interface in ESO is so skeletal that I honestly can't recommend playing without Advanced Filters, Research Assistant, and Foundry Tactical Combat. I prefer to search for things in the game world myself, but I do require access to a reasonable degree of information about the character I'm playing.