There are a lot of dropped plots throughout Marvel history, and many subplots that go unresolved for years or even decades. I'm planning to keep track of these unanswered questions, and do a round-up of them as I reach the end of each year.
(I'm also keeping track of characters that don't receive a real name, because a lot of those take a long time to be revealed.)
Unanswered Questions (as of December 1961)
1) What is the Mole Man's real name?
2) How is it that the Fantastic Four always have clothes that adapt to their powers?
3) What happened to the fourth Skrull impostor?
4) What is the Miracle Man's real name?