I don't have much of a collection, but it has all the ones I could actually need.

Estwing geology hammer
4lb club hammer
rubber mallet
20oz engineering hammer
4oz pin hammer, also good for paint tins

First 3 inherited from my dad who was a paleontologist.
Dumped his collection of sledge hammers because I don't break a lot of concrete these days. I think the largest was 28lb - tried it when I was a kid.