I could see certain "shades" of The Fifth Element in stuff like The Collector's look, the "roguish"-characterizations and humor of Corben Dallas and Peter Quill are parallel, and ofcourse, there's the appearance from actor Christopher Fairbanks that kinda' certifies the winks to that film.
As for Heavy Metal, well, both HM and GOTG have a rock-soundtracks from diverse bands. Heavy Metal also had roguish-characters like Harry Canyon and Captain Sternn, much like Peter Quill is. Harry Canyon, the robot from the HM segment "So Beautiful, So Dangerous", and Rocket have similar type of attitude. Den and Drax are both very strong and bald. And ofcourse, Taarna and Gamora are both d@mn sexy and lethal.