Quote:He has Dormammu, Nightmare and Baron Mordo. Who else does he really have?
Indeed, they are the Big 3.
The others might be the Hell-Lords (especially Satannish, Mephisto and "Satan"/Marduk Kurios), Silver Dagger, the Vampires (especially Dracula and Victor Strange, one of the Baron Bloods), Yandroth and Umar.
Among the lesser known characters, there are the Fear Lords (for example, the Dweller-in-Darkness & Nox) and the Lords of the Netherworlds (for example, Tiboro).
It could be argued that Mephisto is a Fox property because he comes from a Silver Surfer book.
And don't forget Shuma-Gorath.
However, I really don't think any solo hero needs more than 3. By that time, it's time to reboot.