While not tied into the Marvel Cinematic Universe, the animated Guardians TV show still jumps off from the general idea of the movie.
Based on the success of the movie, Marvel started churning out Guardians merchandise and comics, putting a particular emphasis on Rocket and Groot.
It may seem hard to remember, but just a few years ago, Guardians of the Galaxy was still considered a fairly obscure property.
In 2008, however, Dan Abnett and Andy Landing rebooted the team to include Star-Lord, Gamora, Drax, Groot, Rocket, and a number of cosmic-powered characters.