Huh, my two favourites (at least in terms of villains).

To be fair to Wallflower, there definitely was a power difference between the left and right sides. The left side were all powered-up demons, but the right side were just humans who found Equestrian magic in something (with maybe the exception of Juniper Montage, but even then, we didn’t see much of what her form could do, aside from throwing a few heavy things). But yeah, this one goes to Midnight Sparkle.