Marvel has made a few shorts, titled Marvel One-Shots, that introduced characters or enlightened future story points. It was through these shorts that they almost introduced one of their most popular teams in the Guardians of the Galaxy. According to The Story of Marvel Studios: The Making of the Marvel Cinematic Universe (via Screen Rant), Kevin Feige revealed early plans to create shorts for Gamora, Drax, Rocket and Groot, and a young Peter Quill. Marvel hasn't created a One-Shot short since 2014, the year the first Guardians film was released.
As reported in the new book The Story of Marvel Studios: The Making of the Marvel Cinematic Universe, Feige said the following:
"We toyed with the idea of doing short films on Drax, on Rocket and Groot, and on Gamora, leading up to Guardians. This One-Shot series would have led into the Guardians movie proper - which would have also been directly preceded by a fourth self-contained short film about a mysterious kid who loved fantasy things. Then you'd start Guardians. And half-way through, we would reveal that big space hero is the kid from the short. We thought that would be clever, but it was too much."
While these plans are intriguing, especially disguising the identity of Peter Quill, it's hard to imagine the Guardians being introduced any other way than they are in James Gunn's film. The director uses music perfectly in the opening moments of the film to capture the persona and tragedy of Quill. Both 10cc's I'm Not in Love and Redbone's Come and Get Your Love work in stating the kind of character that Chris Pratt's Quill is, with the introduction of the other Guardians following suit in their pursuit of the Orb (eventually revealed to be the Power Stone) and at the Kyln prison.
The One-Shots seem to be a lost art for Marvel Studios, with their last coming in 2014 with All Hail the King, which told the story of Trevor Slattery (Ben Kingsley) following the events of Iron Man 3. If the events of Shang-Chi and the Legend of the Ten Rings are any indication, the One-Shots are certainly a lost art. The other four shorts centered on events central to Phase One of the MCU, with Agent Phil Coulson (Clark Gregg) appearing in the first two, The Consultant and A Funny Thing Happened on the Way to Thor's Hammer. The third, Item 47, focused on a young couple using a Chitauri weapon with criminal intent, while the fourth starred Agent Carter (Hayley Atwell) in the aftermath of the conclusion of Captain America: The First Avenger.
If anything, it's most likely that Gunn's film proved that disparate characters could all be developed and create a solid team dynamic in two hours. And while it's exciting to think about what could have been in these One-Shots, it's hard to imagine meeting the lovable Guardians any other way.