Which comics publishers are there?

The most well-known, thanks to their many film adaptations, are Marvel (Avengers, X-Men, Guardians of the Galaxy) and DC (Batman, Superman, Wonder Woman, Sandman). Then there are, among the numerous smaller publishers, Image Comics (The Walking Dead, Invincible), Dark Horse Comics (Hellboy, Sin City), and IDW Comics (Teenage Mutant Ninja Turtles).