I'm making pretty good progress, here's a few more sprites I did mostly today:
From top-left there's Water Devils, a revamped Drow, (truer to their official appearance) Gremlin, Naga, (possibly Maedar, but they're supposed to be extremely rare so meh, I don't know... perhaps he'll be a boss) Medusa, and last of all Skeletons.
Despite the laughably large heads on the skeletons I'm overjoyed with them, as I've always had trouble drawing skeletons. Now once I get a zombie variation or two I can make an undead dungeon, hurray!
EDIT:Final edit of the Medusa:
The skin tone is more human.