The DragonsCave instance I'm on has a load of custom emojis that I think are quite unique. Naturally there's a load of dragon ones, like whatever :dragon_coolmlem: is. It's called dragon_coolmlem. What's a mlem when it's at home?
There's also a load of eyeless blobcats like :eyeless_blobcat_uwu: (eyeless_blobcat_uwu which I think is an anime smile thing) because the majority of the people on here are blind.