a lot of well known fighters (for tr00 fans) who always get listed in 'legends' threads being listed as 'forgotten'
my choice is gonna be.... ERICA MONTOYA,
who was briefly an early WMMA sensation in the early/mid 2000s, debuting 2 weeks after her 15th birthday (!) and going 6-0... before losing 2 fights in Japan (including her last fight to the definitely-not-forgotton Megumi Fujii), then completely disappeared off the face of the earth, aged 19.
One rumor I read is it was one of those 'pushy parent living out his 'badass ultimate human cockfighter' fantasy through his kid' type deals, she didn't actually want to do it, so she 'ran away' as soon as she reached adulthood.
Nevertheless! she will always hold the distinction of being the first womyn in a UFC vidya gaem, being featured in 'UFC sudden impact' released in 2004.
Here's ingame footage of her beating up George Micha.... uh, Candre Arlovski (a real fight would have gone similar, though I doubt Candre would have got back up after she hit him).
word is this came about because the WOKE(

) UFC was planning to add women as early as 2002-2004, with Erica Montoya vs Shelby Walker (who at one time was dating DENIS KANG - another forgotton fighter?) being worked on as the first bout, but it fell through for reasons I can't remember (or weren't disclosed) and didn't happen for another 10 years (perhaps, because WOKE (

) had not yet been invented in the noughties). But by the time it was cancelled, she was already 'in game'.