Retro, coin-op, fantasy, co-op games that follow DnD classes, and first came to mind are:

Magic Sword

https://en.wikipedia.org/wiki/Magic_Sword:_Heroic_Fantasy

Dark Seal (AKA Gate of Doom)

https://en.wikipedia.org/wiki/Dark_Seal

Also, Magician Lord is a decent fantasy platformer that is listed as multiplayer(I only remember seeing it single player though)

https://en.wikipedia.org/wiki/Magician_Lord

[ Bubble Bobble is the GOAT of arcade coop. Look up the Power-Up cheat code, for input into the attract screen]