This is the master list with the title, the artist(s), and (to save space) only the links corresponding to individual cover images should you want to view them yourself.
Angry Pop Comix, artist: Ethan Van Sciver
Defective Comics, artist: Mike Allred
Legends of the Dork Knights, Pencils: Joe Quesada inks: Jimmy Palmiotti
Adventures of The Man, artist: Chuck Frazier (as "Chuck Frasier" IMDB)
New Jersey Malls 07732, artist: Jae Lee
Buttman Adventures, artist: Kirk Van Wormer
Brandi - The last babe on earth, artist: Jason Pearson
The Incredible Bulk, artist: Dave Johnson
Weapon Sex, artist: Brian Stelfreeze
Fantastic Two, artist: Cully Hamner
Gwen 13, artist: Adam Hughes
Brodieman, pencils: J. Scott Campbell, inks: Alex Gardner (as "Alex Garner" IMDB)
Mallrats, artist(s): Brandon Peterson? No Sig. Cell painting?
My self-help effort started with the IMDB page for the Mallrats film art department, at this point I knew I would be digging in the crates for an answer. I made a list of artists tagged with the credit "main title" and began with those whose drawing styles were known or obvious. Next I started zooming in on the covers to find signatures from the page with the low-resolution cover scans. The signatures I recognized or obviously correlated to the list, I made a note of, and any which were not known to me or too stylized to be legible I began googling artists on the list with "signature" as the additional search criteria. My goal was to answer my own question and create a 2 click compendium for those without the motivation to look further than 2 clicks from their initial search results.
If you have real confirmation that someone did inks on something, or who colored what, feel free to edit with updates but for ease of reading please try to follow the existing format.
Additional main title artists listed on IMDB, credited but unaccounted for: Joe Benitez, David Finch, Frank Gomez, Jason Martin,
Karl Story, Anthony Winn (as Anthony Win)