Yeah, there's a lot actually, so abs is pretty common and so is pbt, but then you get stuff like pom, which is another plastic but often produces a poppy (ish) sound signature. Ceramic keycaps are heavy and have a deep thock to them. There are metal keycaps which are really pricey and sound imo a little pingy but still pretty cool. I'm sure there are others but those are the main ones I see accessable to the general public

I was lucky enough to come in during the era of a bunch of new keycap materials and ended up getting a qk65 with ceramic keycaps, they have a distinctive thock to them and a bit of a ceramic ping on the spacebar and for some reason that is my preference. I consider it my endgame currently just because of the wonderful bounce and sound of the board plus the look is amazing for me.

Black chroma qk65 Gat ink blacks L+F Cerakey indigo ceramic keycaps

But mommm why shouldn't my 5th desk not have a keyboard to accompany it? That would hurt it's feelings

Also not bashing I have the same deal going on