The Merc With The Mouth is ubiquitous in comic books and movies these days, thanks to his fourth-wall-breaking sense of humor. Deadpool sprang from the pages of X-Force to become one of the most successful characters in all of Marvel Comics. Some of that has to do with his humor, and some of it has to do with his costume, which is instantly recognizable to fans everywhere.
As iconic as Deadpool is, he's actually had quite a few variations on the old red and black suit over the years. Like any classic character, there have been a lot of phases he's gone through.
10 Pirate Deadpool
This whacky version of the character appears in exactly one issue, Deadpool Vol 2 #14, but Deadpool as a pirate proved so successful that Hasbro recently made an action figure of him. It's basically just Deadpool in a pirate hat and cloak, with some period-accurate (ish) belts, guns, and swords thrown in for good measure. The elasticity of Deadpool as a character got a real test here, and it proved that the character is basically a chameleon as much as a court jester - he can be anybody.
9 Fantastic Four Welcome Back Party
The Fantastic Four were basically missing from the Marvel Universe for a few years after the Secret Wars crossover event (for complicated Hollywood reasons), but finally, they came back into the fold. Deadpool of all people welcomed them back in Spider-Man/Deadpool #49.
He did so with a variation on his classic costume. The basic red and black color scheme remained in place, but he added brown-leather shoulder pads connected by a strap across his chest. This was a very Liefeld look, though Deadpool never wore such pads in the 90s.
8 X-Men Costume
During the third volume of his ongoing solo series, Deadpool made an honest effort to fit in with the X-Men, but it kind of came out like things usually do with him (i.e. hilariously). Deadpool wore the classic black and yellow training costume very similar in style to that of the New Mutants, with some key differences. The biggest and funniest one was the X-Men lettering he stitched across his chest in red thread. He also kept his traditional red and black face mask, because obviously.
7 Bluepool
Deadpool's desire to become a member of the X-Men kicked off when Beast put him in a team costume as a gag. Deadpool always takes gags seriously, and that led him to experiment with new costumes based on X-Men colors. The most prominent was this blue and yellow outfit from the Cable and Deadpool series.
The costume featured a yellow harness strap that formed a Y shape from his belt up across his shoulders, held together with a signature red X insignia in the middle.
6 X-Force
Deadpool started out as an enemy of X-Force, but like most great anti-heroes, he ended up part of the good guys. If X-Force can really be considered the good guys. Hard to tell sometimes. This costume took his basic red and black look and changed it to gray and black.
Some design elements like the pattern of the grey on his tunic changed, but they tend to subtly from costume to costume. A dark red X belt buckle brought it all together. A version of this appeared in Deadpool 2 after the character got blasted in the final battle.
5 Original Recipe
Deadpool became an instant hit when he debuted in New Mutants #98, right before the team transitioned to X-Force. The original Rob Liefeld design established the basics of the costume - which are in no way derivative of any other costumed hero at another company - particularly the red and black scheme. The pattern of the black portion of the costume was a little more angular in this version, extending through the thighs into the torso. All of that eventually became a little less busy.
4 Weapon X
Eventually, Deadpool participated in the revamped Weapon X program in the early 2000s. This costume brought him even closer to his (not) inspiration, Deathstroke. The entire costume basically inverted, with the black elements becoming orange and the red elements black. The orange patches covering his eyes on the mask were also much larger than on any other costume to that point. He continued to gear up, this time with light-gray belts and harness straps to carry all his awesome weapons.
3 Ultimate Deadpool
Another inverted variation of Deadpool's classic costume appeared in the Ultimate Comics universe. The angular pattern of the original costume came back, though much more exaggerated. The red and black scheme in his face mask inverted, taking on a more sinister countenance.
This version of Deadpool led the Reavers, and basically made life not cool for the X-Men, hunting them like wild game on the living island of Krakoa.
2 Cable and Deadpool
Deadpool adopted a new variant of his costume in the team-up series Cable and Deadpool. This version streamlined the original, with the major addition of a circular red clasp for his harness straps. This clasp gave him a bit of an Iron Man look and didn't appear to serve any practical function - a small clasp would have done just fine - but it was big and bold like Deadpool. He also wore his own Deadpool insignia as his belt buckle, which eventually became a staple of the character.
1 Movie Version
The movie version of Deadpool's classic costume faithfully adapts the comic book look. Some practical concessions are made in terms of making it more padded and armored (especially along the ribs and thighs) but otherwise, it's the comic costume brought to life. And it's the best version of his look so far. Many comic book costumes get bulky - or unusually skinny thanks to being just pure spandex - but not this one. It goes a long way to show how strong a design the original costume was.