What kinds of cards can I use?

Quick answer: lots of them.

Quick caveat: they have to be ARCnet cards.

Long answer:

Almost all ARCnet cards are based on either the old SMC COM9026 chip or chips that are compatible with it. This is pretty convenient, because it means the same ARCnet driver will work with all of them. We call these cards COM90xx cards because of the numbers their chipsets tend to have.

There are some exceptions, though: