Aside from the new added color palettes to Ultimate Marvel vs. Capcom 3, Capcom will be releasing full on costume changes as DLC. The 1st 12 on the left were revealed earlier this year while some appeared in gameplay videos. Since this is the internet, people have pieced together all the other DLC costumes into one big picture.
I totally geeked out for some of these costumes. X may not be in the game but Zero gets a full on X costume and I think that should calm Mega Man fans down a bit for the lack of Blue Bomber in the game. Frank West also gets an X costume of sorts, looks more like a grunt from some 80s scifi flick though.
I'm not going to name all since I barely know half of the references for these costumes.
But to name a few you got Ryu's Fighting Street red hair and red shoes. Chris and Wesker's Resident Evil outfits as well as Jill's Resident Evil 3 clevage top. Morrigan's casual friday clothes. Amaterasu stole the skin of that wolf dude from Dark Stalkers. C. Viper in.... something. Viewtiful Joe in "Joe" mode (Pre-Henshin a Go Go Baby). Chun-Li's sexy Street Fighter Alpha tights and Phoenix Wright totally sporting his "I heart Feenie" shirt that he wears during a flash back in Phoenix Wright: Trials and Tribulations.
On the marvel side we have a mohawk Storm, X-23 in her (I would like to say) X-Men Evolution look. Scarlet Spider for Spidey-man (woot). World War Hulk is in there, A more classic Sentinel. Doom in his swim gear. Phoenix in her 90's Jean Grey outfit (nice). Deadpool wearing Cable's belts... and hair. To top it all off we got an Elvis M.O.D.O.K.
"Click the image to get a better look"
Thanks to @estimater for showing me the pic