These are all of Doctor Doom’s appearances in the 1960s.
Cameos are reviewed separately.
Fantastic Four #5
Fantastic Four #6
Fantastic Four #10 (the mind switch story)
Fantastic Four #16 (Ant-Man)
Fantastic Four #17
Avengers #1.5 (continuity insert)
Amazing Spider-Man #5
Fantastic Four #23
Fantastic Four Annual #2 (main story)
Fantastic Four Annual #2 (Doom origin)
Fantastic Four #39
Fantastic Four #40 (THE Doom vs Thing story)
Fantastic Four #43 (cameo only)
Fantastic Four Annual #3 (marriage of Reed & Sue)
Avengers #25
Fantastic Four #57 (begins the “Doom steals Silver Surfer’s power” storyline)
Fantastic Four #58
Fantastic Four #59
Fantastic Four #60
Daredevil #37
Daredevil #38
Marvel Super-Heroes #20 (first Valeria)
Fantastic Four #84 (the “Prisoners of Latveria” storyline)
Fantastic Four #85
Fantastic Four #86
Fantastic Four #87
Sub-Mariner #20