Most covers for a superhero comic book

Marvel's The Amazing Spider-Man issue 666 – the prologue to Dan Slott's "Spider Island" story arc – was sold with 145 variant covers. This is the most by a solid margin; 41 more variants than Godzilla: Kingdom of Monsters #1 from IDW. Most of the variants for this issue had covers dedicated to individual comic-book retailers such as Flying Colors (in Concord, California, USA) or Forbidden Planet (in London, UK).