So we currently have Gold skeletons, Shadow Skeletons and Plant Skeletons. i think we need more and this post is to think up more types, with strengths and weaknesses.

Fire/Coal Skeleton- first of all for equipment, they carry a torch and grog that they use to light themselves ablaze and breath fire. Strengths, when lit on fire they attack faster as well as having a chance to light you on fire for a DoT effect. Weaknesses Water, Water makes them start to smolder making them slower and easier to damage.

Ghost Skeleton, Strengths, immune to all physical damage, can take control of a player for short periods of time. Weaknesses, Burns in sunlight and only sunlight, can be shot out of a players body by being in/splashed with water, dies instantly when you show them your clock as it reminds them of the time they died, causing them to disappear.

i'll add more as i think of them, feel free to add your own ideas though.