Great server(s) with different versions of WoW and different class structures. Rexxar server has 21 completely new classes instead of the default classes bit is otherwise Vanilla Wow. Area 52 server has no classes and you mix and match abilities from all the standard characters in WoW. Al'ar uses random skill cards awarded as you level up, meaning you use a skill from the ones you are dealt or try re-rolling the cards if you get a bad deal. Area 52 and Al'ar are up to Burning Crusade expansion. There is a test server for Wrath of the Lich King, and at this time both Rexxar and WotLK are accessed by a donation.
I love the new classes - particularly the Necromancer, always my favourite class. Area 52 and Al'Ar are playable free and I am currently have a lot of fun on Area 52. It was on the strength of the fun I had in Area 52 that I donated in order to try the 21 new classes on Rexxar.
https://ascension.gg/