Before there was a Marvel Comics Publishing house, there was a company called Timely Publications. The very first comic they produced in October 1939, Marvel Comics #1 would star The Human Torch, Namor The Submariner, the Angel and Ka-zar the Jungle lord.
Later, they would change their name to Timely Comics and publish more well known characters such as Captain America and his sidekick, Bucky. Eventually, in 1961, Timely Comics because Marvel comics and we know how well that turned out.
Due to the historical nature of Timely Comics, I felt it was worth keeping an eye out for any 1st Appearances.
1ST APPEARANCE OF ADVENTURE TIME WITH FINN JAKE IN COMICS RARE FCBD
Time Remaining: 11d 22h 47m
Buy It Now for only: $20.99
KURT BUSIEKS ASTRO CITY NO1 2 ALEX ROSS COVER 1ST APPEARANCE OF TIME KEEPER
Time Remaining: 13d 2h 39m
Buy It Now for only: $2.49
ARCHER ARMSTRONG 8 1ST APPEARANCE IVAR THE TIME TRAVELER
Time Remaining: 16d 4h 41m
Buy It Now for only: $10.49
AMERICAN FLAGG 1 3 1983 FULL RUN OF HARD TIMES 1ST APPEARANCE TV SHOW NM
Time Remaining: 21d 4h 42m
Buy It Now for only: $13.49
Adventure Time Spooktacular 1 VF NM 1st Appearance Steven Universe
Time Remaining: 22d 23h 32m
Buy It Now for only: $14.99
Batman 442 1st First Appearance Of Time Drake As Robin In Old Suit NM Near Mint
Time Remaining: 25d 3h 21m
Buy It Now for only: $4.99
1ST APPEARANCE OF STEVEN UNIVERSE IN COMICS ADVENTURE TIME 2013 SPOOKTACULAR
Time Remaining: 28d 15h 9m
Buy It Now for only: $11.99