I recently posted my piece of amber with a small gnat relative encased inside in the recognizing fake fossils subforum. In that thread @caldigger and I were talking about how an insect in amber is a staple for any fossil collection. That got me thinking about what other fossils would be good inexpensive (or expensive, I don’t judge) fossils that are also must-haves of collectors. Of course, being from the West, I thought about Knightia eocaena and Elrathia kingii. What do you guys consider to be the collector’s classics?