I've been drawing some monsters in my free time recently and here are some slimes I came up with. I think there are a lot of ways to add some variety to the classical circular blue slime thing from the beginning of every rpg ever.

Also I am planning to use most of these in a puzzle game I'm making for fun, available for free on itchio: https://ultra-shenanigans.itch.io/human-upgrade-labs And it already has a lot of monsters and various creepy spooky things.