Database: Costumes

Note that I will not be listing uniforms worn by alternate reality and/or timeline members of the FF. And, yes, I'm aware that I haven't listed all of Ben's or any of Crystal's uniforms yet. There are considerably more variations and I am still working to document them all.

The first "uniform" the team wore was actually the flight suits they had on during their exposure to cosmic rays in Fantastic Four #1. Although the actual comic itself depicts the colors as being blue with white highlights, every retelling and reprint since then has presented them as purple and blue.
This is generally considered the "classic" FF uniform. It was designed by Susan Richards (then Storm) and debuted in Fantastic Four #3.
The Thing was uncomfortable in his original costume, so by Fantastic Four #4, he had trimmed it down to only include shorts, a belt and boots.
Still somewhat uneasy, Ben eliminated the use of boots in Fantastic Four #5 and spent much of his time in what is considered his classic outfit.
In Strange Tales #106, Johnny briefly joined forces with The Acrobat to discover -- and thwart -- his plans. This costume was designed and given to Johnny by The Acrobat.
Reed borrowed this costume from Nick Fury in Strange Tales #127 to conceal his identity from Ben and Johnny during an impromptu training exercise.
In Fantastic Four #68, Susan played a little with her original costume design to better accomodate her pregnancy. She wore this only briefly before taking a temporary leave of absence from the group.
After a devastating battle against Omega, Johnny used Inhuman technology to give himself a new uniform design in Fantastic Four #132. It's clearly an amalgam of his former uniform and the costume worn by the original android Human Torch.
After Ben was transformed back to his human form, Reed need a replacement member until he could complete Ben's exoskeleton. Power-Man was hired in Fantastic Four #168, but kept his existing costume while he was with the group.
After losing his powers, Reed Richards was unwittingly duped into helping Dr. Doom capture the other members of the Fantastic Four. To that end, he donned the Invincible Man costume in Fantastic Four #196. Interestingly, an alternate reality Reed donned the costume in Fantastic Four #388, calling himself the Dark Raider.
Returning from the Negative Zone in Fantastic Four #256, the Fantastic Four found that their costumes had become 'negative' versions of their originals.
After dating Johnny for some time, Frankie Raye discovered that she also had similar powers. Her stepfather, Thomas Horton, created this uniform for her shortly after she gained her powers in a lab accident and used hypnosis to make her forget the incident. When Frankie was asked to join the FF in Fantastic Four #239, she simply continued to wear the outfit.
Helping Spider-Man teach some kids a lesson in Peter Parker, Spectacular Spider-Man #103, Johnny briefly claimed the identity of Blaze.
In the last issue of Marvel Super Heroes Secret Wars, Ben wished to stay behind on the Beyonder's world. To keep from causing too much undue stress to the rest of the team, he asked She-Hulk to take his place. She accepted and created a stream-lined version of the FF's latest uniform.
Being mentally controlled by Psycho-Man, Susan enacted her 'revenge' on the other members of the Fantastic Four. She concealed her identity behind a 'Malice' persona starting in Fantastic Four #280.
After a bout with further mutation, Ben returned to the FF. Although he had returned to his "normal" rocky appearance, his unease led him to briefly utilize a full body-suit costume starting in Fantastic Four #302. Shortly afteward, however, he returned to his black shorts.
In Fantastic Four #359, Ben took to wearing long pants and boots.
In what some claim as another lapse into her 'Malice' persona, Susan donned a very revealing version of her black uniform in Fantastic Four #371.
After getting his face hacked up by Wolverine in Fantastic Four #374, the Thing once again donned a helmet to hide his looks.
By Fantastic Four #377, Ben became even more self-conscious of his appearnace and started wearing a tank top as well.
After hiding his face for some time after being slashed by Wolverine, Ben removed his helmet in Fantastic Four #386.
Gaining some of her senses back, Susan tempered her previous outfit with some modesty in Fantastic Four #388.
Although no reason was given, the Fantastic Four jointly redesigned their costumes in the midst of Onslaught's menace, as seen in Fantastic Four #415.
The heroes ended the Onslaught affair and were sent over to a Counter Earth by Reed and Sue's son, Franklin. They relived their early adventures there and modified some S.H.I.E.L.D. uniforms to identify themselves in Fantastic Four volume 2 #2.
Upon returning to their home planet, the FF returned to a look reminiscent of their original costumes in Fantastic Four volume 3 #1.
Reed, having defeated a Celestial and deserving of punishment in said Celestial's eyes, found himself trapped in Dr. Doom's armor at the end of Fantastic Four volume 3 #25. Interestingly, Reed had already found his mind trapped in Doom's body (and armor) as early as Fantastic Four #10.
In Fantastic Four volume 3 #27, Johnny took to wearing a non-uniform style jumpsuit with no explanation given.
Although Susan's uniform ripped in a similar fashion earlier, it wasn't until Fantastic Four volume 3 #28 that she permanently modified her uniform shirt into a tank top.