Oh. Well. I mean... Sort of but. Also no.
You can't summon a giant spirit from another world to do your fighting so much as...
'This weapon was imbued with magical energy and can deal elemental/other types of damage besides physical' or 'this necklace is enchanted to protect the wearer' or...
So. Most classes are just divided by 'holder' or well, magic items.
And the rest are what I consider 'magic energy' classes. If you can make it fit, it can exist.