Borderlands 3 developers Gearbox have a display at San Diego Comic-Con called the Museum of Mayhem where they're showcasing their game's rejected cover art. Some of it's gorgeous, and over on the Resetera forum poster vestan has photographed the highlights. It's hard to go past the one with the foot, which solves the problem Gearbox set for themselves by having the fingerguns psycho shooting himself with one hand on the front of the first game and two hands on the second. What could have been!
Plenty of the others are great as well, especially the one with the stark black silhouetted figure on a white background, and the one with a gun for a head. It's pretty obvious why the breastfeeding image didn't make the cut, however.