UFC Record: 0-1
Top Wins: Caol Uno, Frank Trigg, Dave Menne, Shinya Aoki (X2), Jens Pulver, Joachim Hansen
Sakurai's single UFC fight was a welterweight title bout with Matt Hughes. Although he never competed for the promotion again, I think he would have been a perennial contender in the more appropriate 155-pound class.
UFC Record: 4-0
Top Wins: Paul Varelans, Hugo Duarte, Daniel Bobish, Enson Inoue
Kerr was primed to avenge his training partner Mark Coleman and reclaim the UFC heavyweight title from kickboxer Maurice Smith. Instead, he left the UFC entirely during a contract dispute and his career fell apart in a cloud of drug abuse and disarray (see the HBO documentary The Smashing Machine).
UFC Record: 1-0-1
Top Wins: Royler Gracie, Royce Gracie, Renzo Gracie, Quinton Jackson
An all-time MMA great, Sakuraba spent his best years in the Pride promotion, competing in a division featuring fighters at least 20 pounds heavier than he was. At 170 or 185 pounds, the catch wrestler might have become the most accomplished fighter ever. But we'll never know.
UFC Record: 15-6
Top Wins: Matt Hughes, Paul Daley, Diego Sanchez, Chris Lytle
Koshcek lost his one title bout by unanimous decision, unable to solve the riddle of Georges St-Pierre. Other potential title shots evaporate with untimely, and often unexpected, losses.
UFC Record: 3-5-2
Top Wins: Rumina Sato, Mitsuhiro Ishida, Din Thomas (X2), Yves Edwards
Uno had his shot at UFC gold, going to a draw with B.J. Penn at UFC 41 with the belt on the line. With no champion to crown, the UFC shelved the division all together.
UFC Record: 7-5
Top Wins: B.J. Penn, Paul Daley, Frank Shamrock, Robbie Lawler
One of the sport's most polarizing figures, Diaz fell short when he finally got a chance to compete for UFC gold. A long-time Strikeforce champion, Diaz hopes to finally get a shot at champion Georges St-Pierre in 2013.
UFC Record: 10-4
Top Wins: Ivan Salaverry, Shonie Carter, Jeremy Horn, Demian Maia
Marquardt, a former King of Pancrase in Japan, fell short against Anderson Silva in 2007. Since, he's twice lost title eliminators, once to Chael Sonnen and once to Yushin Okami. Currently biding his time in Strikeforce, Marquardt is counting on a move to welterweight reviving his title dreams.
UFC Record: 9-3
Top Wins: Ricardo Almeida, Phil Baroni (X2), Travis Lutter, Jeremy Horn
The former Olympic silver medalist lost twice in his lone UFC title shot. Referee John McCarthy missed his initial tap, so Murilo Bustamante had to finish Lindland a second time. A contentious relationship with UFC brass helped prevent the wrestler from ever securing another title bout.
UFC Record: 6-7
Top Wins: Chuck Liddell, Forrest Griffin, Chael Sonnen
Jeremy Horn's first UFC fight was a title shot, and he took Frank Shamrock to the limit. Horn was likely on his way to a decision win when Shamrock pulled off a last second knee bar submission. Horn would get another shot late in his career, falling to Chuck Liddell. During his best years, the globe-trotting Horn never stuck around in the UFC long enough to claim gold.
UFC Record: 2-2
Top Wins: Dominick Cruz, Jens Pulver (X2), Brian Bowles
Two of Faber's four UFC fights have been for the strap. He fell short both times. But the charismatic star seems destined to get another chance at securing his legacy as one of the most important lighter weight fighters ever.
UFC Record: 2-2
Top Wins: Dan Henderson, Robbie Lawler, Yushin Okami, Carlos Condit
While he reigned in Strikeforce for years, many considered Jake Shields the best fighter in the world outside the UFC. He got a chance to prove it in the Octagon, but fell short against Georges St-Pierre. Only time will tell if he can regain the form that once made him one of the most feared submission artists in the game.
Norifumi "Kid" Yamamoto
UFC Record: 0-3
Top Wins: Royler Gracie, Caol Uno, Genki Sudo
Yamamoto was a shell of his former self by the time he stepped into the UFC Octagon. In his prime, he dominated the Japanese scene, often giving up 20 or 30 pounds to fight in the lightweight division, despite being a natural 135-pounder.
UFC Record: 2-3
Top Wins: Hayato Sakurai, Jens Pulver, Ralph Gracie, Rumina Sato
The top star of Japan's Pride Bushido offshoot, the lightweight star wasn't able to recapture the magic he made in the ring when it was time to make the move into the cage. Approaching his 34th birthday, Gomi seems likely to end his career without ever wearing the UFC belt.
Mirko "Cro Cop" Filopovic
UFC Record: 4-6
Top Wins: Kazushi Sakuraba, Josh Barnett (X3), Mark Coleman, Wanderlei Silva
One of the best heavyweights ever, Cro Cop was no longer a top competitor once Pride collapsed and he made his way to the UFC. In his Pride prime, however, his deadly striking made him one of the most feared fighters on the planet.
Antonio Rogerio Nogueira
UFC Record: 3-2
Top Wins: Tito Ortiz, Dan Henderson, Guy Mezger, Kazushi Sakuraba
The twin brother of former interim heavyweight champion Antonio Rodrigo Nogueira, Rogerio has spent his entire career as a light heavyweight. He combines a solid boxing game with his superlative jiu jitsu. At 36, it may be too late to make his title run.