The 12% Joke
In The Avengers When Tony Stark tells Pepper Potts to give herself “…12% of the credit” for creating Stark Tower. Pepper is not amused (and no doubt insulted, I mean come on! Tony would crash with out her!) by the absurdly low number, and later throws the number back at Tony saying that she was “having 12% of a moment.” James Gunn featured a throwback to Joss Whedon’s 12% joke in Guardians of the Galaxy. When Star-Lord announces his plan to the rest of the team in preparation for the third act battle, Rocket Raccoon (Bradley Cooper) and Gamora (Zoe Saldana) try to explains that 12% isn’t a plan, it's “barely a concept.” Could this be a connection of some sort?
She plays Peter Quill’s mother, Meredith Quill and also was the autograph girl in the first Captain America: The First Avenger. If the time period wasn’t so off you could have thought Meredith Quill might have met good Ol' Captain America. You never know, she did have that year long fling with Peter's father J’son who is a Emperor Star-Lord (hopefully we see his father in the next Guardians of the Galaxy).
The Planet of Morag
After the opening of the film, we see the now grown up Star-Lord on the planet of Morag. Peter Quill has landed on what appeared to be a deserted wasteland planet in hopes of stealing a treasure hidden inside the temple ruins, lost for many centuries (definitely an Indiana Jones inspired moment). The planet doesn’t appear in the Marvel comics but the name Morag is a tribute to the first leader of the Kree.
The Infinity Gauntlet
It has already appeared on screen in a Marvel Studios film, however very briefly. The infamous glove could be seen in the background of Odin’s treasure room during the attack by Frost Giants in Thor.