Trivia: When Ryan Reynolds goes to the facility to become a superhero, as he's being wheeled through the doors on the gurney, he asks (in regards to when he gets his superhero suit) if it can not be green, and also that it be a real suit and not a CGI one. Both these statements are in reference to the badly-received "Green Lantern" movie which starred Ryan Reynolds in the lead role.
Trivia: The joke that Deadpool makes "It's almost like the studio couldn't afford another X-man" is actually true. The movie had a relatively meagre budget of $58 million and the studio could not afford more X-men. The fight scene at the end in the junkyard also originally had Deadpool killing everyone with guns, but that was replaced with swords for budget reasons as well, which is why he accidentally leaves his bag of guns in the cab.
Trivia: In the comics, Negasonic Teenage Warhead's powers are vastly different than what is shown in the film. In order to get Marvel's approval to change her powers for the film, Fox was forced to relinquish the film rights to the character Ego the Living Planet, who was packaged with the Fantastic 4 film rights. Ego will appear in Guardians of the Galaxy, Vol. 2 portrayed by Kurt Russell. Similar to Negasonic Teenage Warhead being named after a Monster Magnet song, Monster Magnet has a song named after Ego the Living Planet, which can found on the same album.
Trivia: This film spent several years in development hell largely because Fox wasn't sure that the film could be profitable, based in part on the character's negative reception in "X-Men Origins: Wolverine" and desire by the filmmakers for it to be rated R. It wasn't until computer animated test footage was leaked online to universal praise that the film was finally given the green light. Despite the hurdles the film had to overcome to get made, it ironically became not only the highest grossing film in the X-Men franchise (both domestically and worldwide), but the highest grossing R-rated film of all time worldwide.
Trivia: The Dead Pool betting board (The "Daisy Pushers Club") includes several names of famous and semi-famous people... The person at the bottom right corner, "A. Palmer, age 86" appears to be a reference to Arnold Palmer, who passed away a few months after Deadpool was released, on September 25, 2016... At age 87.
Trivia: There are two post credits scenes, one where Wade talks about Cable - the son of Madelyne Pryor (Jean Grey's clone) and Cyclops.