These are all of Doctor Doom’s appearances in the 1980s.
Cameos are reviewed separately.
That time Doom met Superman is not part of the retrospective.
Or the Fantastic Four #330 apocrypha.
Or the Solarman story, because nobody cares about Solarman.
Fantastic Four Annual #15
Dazzler #3-4
Iron Man #149
Iron Man #150 (“Knightmare”)
Uncanny X-Men #145
Uncanny X-Men #146
Uncanny X-Men #147
Fantastic Four #236 (“Terror in a Tiny Town”)
Fantastic Four #237 (cameo)
Micronauts #41
Fantastic Four #246
Fantastic Four #247 (“This land is mine!”)
Fantastic Four #258
Fantastic Four #259
Fantastic Four #260 (Doctor Doom’s “death”)
Secret Wars #1
Secret Wars #2 & 3
Secret Wars #4 & 5
Secret Wars #6-7-8
Secret Wars #9
Secret Wars #10
Secret Wars #11
Secret Wars #12
Beauty and the beast #1-4
Fantastic Four #268,278,279
Fantastic Four #287
Fantastic Four #288
Emperor Doom
Cloak & Dagger #10
Fantastic Four vs X-Men
X-Factor Annual 4
Fantastic Four 305
Fantastic Four Annual 20 (Kristoff takes Latveria)
Fantastic Four #311
Fantastic Four #312
West Coast Avengers #35
Damage Control #2
Fantastic Four #318-319 (“Secret Wars 3”)
Fantastic Four #320 & Hulk #350
Marvel Comics Presents #48 (the most unnecessary Doctor Doom you’ll ever read)
Iron Man 249
Iron Man 250 (a.k.a. “Knightmare 2”)
Thor #409-410
ACTS OF VENGEANCE
Doom’s Vengeance Acts: Avengers (Avengers #311/313 and Captain America #365/366)
Doom’s Vengeance Acts: Spider-Man (Spectacular #158/159/160, Amazing #327, Web #59/60/61)
Doom’s Vengeance Acts: Punisher (Punisher #28/29, Punisher War Journal #12-13)
Doom’s Vengeance Acts: cameos (Daredevil, Hulk, Cloak&Dagger, Fantastic Four)
Power Pack #53
Doom’s Vengeance Acts: the ending (Avengers West Coast #55, Avengers Annual #19)
There are also a few continuity inserts set in the 1980s.
Triumph And Torment was published in the 80s, but it’s chronologically in the 90s.