One of the best stories is when they teamed up to defeat Ronan the Accuser. They overcame their differences and individual flaws to work as a team and save Xandar. It was a great display of their growth as a group.
Another great one is 'Annihilation: Conquest - Star - Lord'. This graphic novel delves deep into the character of Star - Lord. It has a complex plot that involves the Guardians in a battle against powerful forces. The art style is detailed and helps to create a vivid and exciting universe for the story.
Well, Tumblr can be a great place too. There are often users who share their Guardians of the Galaxy fanfiction pieces, either directly on their blogs or by reblogging others'. Additionally, Wattpad might have some interesting takes on Guardians of the Galaxy stories, although it has a wide range of content so you may need to do some searching.
Star - Lord is an obvious choice. His dual identity as a human from Earth and a galactic hero gives a lot of scope for character exploration. You could write about his struggle to balance his two lives, or how his memories of Earth influence his decisions in the galaxy. Drax is also interesting. His quest for revenge and his unique way of seeing the world can be the center of an engaging fanfic.
The Guardians of the Galaxy comics are known for their humor. The combination of the characters' personalities and the creative storylines contribute to the funny aspect. Some issues are funnier than others, but overall, they have a good dose of comedy.