@Dirt
Constructs deal a LOT of Elemental... in particular Gun Puppies, Retrodes and Mecha Knights. Gremlins deal some too, but it's almost all normal.
So, though Elemental is dealt by few enemies, they are nasty ones. Expecially Gun Puppies when there is a lot of them.
It could also be noted that there are three main levels/environments you can find at any point not depending on stratum theme:
- Danger rooms ---> mainly Piercing
- Graveyards ------> totally Shadow
- Arenas -----> always lots and lots of Elemental due to Puppies and Mechas
and Arenas are by far the thoughest if you do all 3 stages, that's why Elemental protection is a must have...
Beasts and slimes deal piercing.
Undead and Fiends deal shadow.
Gremlins and Constructs deal normal.
If anything Elemental is the least common type of attack with it being sprinkled about within the enemy types. I could be somewhat wrong, but this is based on my experience and what some of the Wiki has to offer.