Dr Doom, in the comics, is Victor von Doom. He's a scientific genius with a penchant for sorcery and a desire for world domination. His complex personality and advanced technology make him a formidable foe.
Dr Fate is a significant character in DC. He has a mystical helmet that grants him immense powers and a connection to the forces of magic. He's been a part of various DC storylines and teams.
Tony Stark isn't Dr Doom. They have their own separate identities, backstories, and roles in the comic universe. Dr Doom is a powerful villain, while Tony Stark is the genius behind Iron Man.
There are quite a few Dr. Doom comics. It's hard to give an exact number as new ones are constantly being produced and old ones are re-released in different editions.