The Flash

Sure, the prospect of Supergirl crossing over with any of the CW DC shows seems bleak at best, but this is a list about who we WANT to see, not who we EXPECT to. And if we're playing by those rules, The Flash definitely makes the cut. The Flash and Supergirl have partnered (and even faced off) a lot in the comics, and there's no denying that Barry Allen would feel right at home on Supergirl (more so than Oliver Queen, at least). Seeing the two team up on the small screen would be the Justice League tease we've all been waiting for, and could lead to an excellent hour of television. It may be a long shot, but hey, if The Flash is going to explore the Multiverse next season, maybe there's a chance these two cross paths!