How many map bosses are there?

I'm struggling to find more than 7 or 8 enemies that are considered map bosses is that right?

I've listed them here(

Cow bell boy
Swamp lady
Ice hag
Bone witch(flying)
Skeleton
Titan guy
Lady and her pet elephant
Laser madusa

I thought there were over 100 bosses, does it get better as I do more endgame.

Also I've only seem 1 while in over 30 maps is that normal