Collecting

It would be interesting to hear how people choose what cards to keep in their collections (or choose to hunt down).

Some speculative ideas from someone just getting into magic. Feel free to comment on any of them or add your own thoughts.

1. Gameplay utility, just being a good card in some format or another
2. Being a fun card to play, having some amusing qualities for kitchen table play
3. Monetary value
4. Art, cards with art that appeals to you
5. Artist, cards with art done by a certain artist
6. Theme, maybe you're trying to collect all cards with airships on them, or with a particular mechanic
7. Type, all rat creature cards will be mine
8. Completing a set, collecting all cards from a particular set