Some big names you can google (not all of them specifically PvP focused): Alcast, SypherPk, Deltia.

They all have build videos you can watch to get an idea of what looks interesting.

Basically you have 8 build types to choose from. Each of the four classes can be played with more of a magicka focus or a stamina focus. I'm not an expert on every class, but here are some general highlights:
Magicka Sorcerer - strong damage shields, synergy with lightning damage, burst mobility, timed damage burst (ranged), summoned pets (though they have drawbacks)
Stamina Sorcerer - hurricane (powerful dot, sustained mobility), stong synergy with physical attack types (melee)
Magicka Nightblade - cloak (short-term invisibility), strong crowd control skills, can fight melee (with class skills) or ranged (with staff)
Stamina Nightblade - strong synergy with disease damage (melee), also good crowd control, some very strong burst attacks
Magicka Dragonkight - strong synergy with flame damage, lots of damage over time attacks, usually fights in melee range, some good tanky skills
Stamina Dragonkight - strong synergy with poison damage, lots of damage over time attacks, melee, good tanky skills
Magicka Templar - powerful healing skills, radiant destruction (Jesus beam), main spamable attack is a conal aoe that also heals you
Stamina Templar - this one I don't feel like I know enough about to mention, but suffice it to say it can perform well and has room for being more tanky or more of a damage dealer depending on your build layout.

None of the class setups are worthless. Some will perform a bit better than others in various circumstances, but it's learning to play your character well that will make the most difference.

Good luck to you in your journey!