My guess is that we'll probably see a team up of some of Equestria's greatest threats as part of a sort of "Legion of Doom" in Season 9. If so, we'll probably see Cozy Glow and Tirek escaping Tartarus, to which they start recruiting villains such as Chrysalis andAhuizotl (or maybe even The Sirens since we haven't seen them since the end of Rainbow Rocks). And if the Season 9 leaks are true, we could see the likes of Grogar and Kind Sombra joining their cause. There's absolutely no way Cozy Glow isn't coming back if the Season 8 finale is anything to go by