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The idea of a self-contained mind spontaneously appearing into existence, similar to Ego the Living Planet (Kurt Russell) in this movie, is called "Boltzmann brains." The argument suggests that in a universe that exists forever, one is more likely to be a Boltzmann brain hallucinating reality than a real being.
Prop master Russell Bobbitt had difficulty finding the cassette decks used in the first film, and all of the Sony Walkman headphones they found were broken. Bobbitt contacted Sony to see if they had any available for filming. They did not, so he eventually created six from scratch.
Dave Bautista's Drax make-up took 90 minutes to apply (down from three hours for the first film). However, he would have to sit in a sauna at the end of the day in order to get the make-up off.
When director James Gunn was writing the script for the movie and proposed the idea of Ego the Living Planet being Star-Lord's father, Marvel Studios told him that they did not have the rights to the character. The rights belonged to Twentieth Century Fox because of his ties to the Fantastic Four and Silver Surfer franchises. Since Gunn had no other characters in mind for Star-Lord's father, he had to ask Fox if he could use the character. Fortunately, Fox agreed to let Marvel have Ego, in return for Fox gaining more creative freedom over Negasonic Teenage Warhead's set of superpowers in Deadpool (2016).
According to the visual effects artists, Ego's planet contains one trillion polygons. At the time of the film's release, this was considered to be the biggest visual effect ever made.
In the Guardians of the Galaxy comics, Taserface is a warrior from the cybernetically enhanced race known as The Stark. The Stark are an alien race that found Iron Man technology that had accidentally crashed on their planet, and as a result they worship Tony Stark (Iron Man) as their god.