Doctor Strange is my favorite Marvel villain since Spider-Man has such a big following so it's almost crazy for me to consider Doctor Strange as being a villain of any kind. He's more focused on the occult world and healing rather than fighting crime. What most fans don't appreciate how dangerous he is because when we learned his magic he got sick the moment the sun hit and made him feel weird and sick, this caused major altercations and So many times he was seen lying unconscious, this only added to his already serious nature when the sun hit his body and it took over his mind. He usually does work with other evil entities or even the dead, but I guess it wouldn't be hard for him to bring them here on earth to finish a job here. If he wasn't able to do so I don't see why he wouldn't be a powerful foe. He's a genius at making people believe that he can just fly around the world and control everything, but in reality, he's got a lot of power.
Watch : Doctor Strange Multiverse Of The Madness