Video:
https://www.youtube.com/watch?v=9BbgROZ9STY
Video features crazy player created specs from Wrath era:
-Honor Among Thieves Rogue
-AoE Fan of Knives interrupt and silence Rogue (pvp)
-Spell Power Enhancement Shaman
-Prot Holy Paladin (converting stamina into spell power...later changed to strength into spell power)
-Preg Pala (Prot Holy Ret Paladin)
-Necromancer caster ranged Deathknight (pvp)
-Dancing rune blood DK DPS (pre nerf)
-Arms Prot Tank Warrior
-Frostfire Mage
And there were many more player created inventions in specs some of which had to be nerfed.