Fusions are just so cool! And there are still new designs that we haven't seen yet! Each new gem means a ton more combos to see! And you know what we haven't seen yet? Ruby and Sapphire individually fuse with somebody (aside from themselves). That'd definitely be an interesting episode. It's neat that we've finally seen Steven's first gem fusion as well, and now know that he can fuse with gems and humans! So much cool stuff happening.