Propose a team-up of characters you don't think have ever teamed up before. Just so this thread doesn't become a list of names, give at least one reason you want to see these characters team up or why this pairing would be interesting. And if someone proposes a team-up that has actually happened, please let us know! (and I don't mean "they fought next to each other in some crossover event", I mean a proper team-up or at least a meaningful interaction)
I'll start:
Sandman (Dodds) and The Question (Sage): these are two investigators who think outside the box and do more than beat up criminals. They have some understanding of the metaphysical and it would be interesting to see their points of view while investigating a difficult crime.