Planescape heavily features the Psionic Gith.
That's the other extremely desired Setting people are still clamouring for. Psionics are also not alien to Spelljammer, too (another popular setting). Giff in UA suggest Spelljammer. Thri-Kreen suggests Dark Sun.
It's possible we'll get a gazetteer of various other D&D Worlds, or something, too. :/ But I think if they don't give us any of these settings soon, there will be riots. MtG settings will still come out likely 1 per year or 1 per 2-years, but if it's ONLY Critical Role and MtG settings then there WILL be riots.