Currently, a deck of cards has a royal theme with kings and queens, and a general ranking system with numbers, but I want to shake things up a bit.

I've created a new card game which...could use a regular deck, however I'd like to create a customized deck I can sell. The ranking system doesn't matter, it's just a matching system. You have diffrent suits, and then 10 distinctly diffrent cards in each suit...plus a bunch of challenge cards mixed into the deck.

So rather than just numbers 1-10, what should be on the cards to distinguish them apart? I'm looking for something basic. No chance of royalty claims or anything from movie franchises thinking I'm trying to copy them. Something that represents items to collect. I was thinking maybe some kind of gems. Maybe pieces of a suit of armor or something.

Does anyone have any other ideas? What else could be used instead of a standard deck of cards?