Each class should totally have a mount like Conjurer.

Gladiator - No clue..... Griffin might be good for them instead? White Wolf?
Marauder - Griffin or Tiger?
Lancer - Drake/Dragon/Badass scaled monster
Pugilist - Tiger might work for them, or one of those giant buffalos?
Archer - Maybe a Phoenix type thing?
Conjurer - Unicorn :P I thought a tree mount would be cool for them, but eh
Thaumaturge - Something cooly elemental, chimera or hydra type thing?
Arcanist - First thing that comes to mind is a flan/pudding haha, but im not sure on this one