Scott Pilgrim's Precious Little Life
August 18, 2004
The band that Scott plays in, introduced in the first volume, is named "Sex Bob-omb" and their symbol, featured on the drum, is an angry Bob-Omb (though it might also be based on Serious Sam's logo). This is retained in the movie.
Then in a scene, while playing with his band in a dream, Scott is wearing a t-shirt with what appears to be a Starman on it. This may be a generic star however.
In chapter 4, when Ramona explains to Scott how the Subspace Highways work, he asks if it's like in Super Mario 2, and after a pause she answers "Ummmmmm... No. It isn't really like that at all." However, the star-emblazoned doors Ramona uses to enter subspace were inspired by the design of the doors in Super Mario 64. The subspace door is also seen in the movie.
Scott Pilgrim vs. the World (book)
In Chapter 11 of the second volume, when Ramona asks Scott if they were "an item", he responds in confusion and Mario items appear in a thought bubble next to him, precisely a Super Mushroom, a Star and a Fire Flower.
Scott Pilgrim's Finest Hour
In the sixth and final book of the series, Scott pictures himself wearing a Tanooki Suit when he tries to remember what his relationship with Envy was like.
Scott Pilgrim vs. the World: The Game
August 10, 2010
In the Scott Pilgrim videogame the Subspace Highway bonus areas feature blocks similar to the ones from the Mario series.
Additionally, When Stills finishes a level, he jump into what appears to be a Warp Pipe.
The creators of Scott Pilgrim didn't hold any right over Nintendo's Mario, but they only included a minor reference.