Quick note: wrestlers like Samoa Joe and Robert Roode were excluded from the TNA section of this list, since most fans easily associate them with TNA.
Ah, WCW and TNA - once thought of as competition for WWE, now just tombstones in the graveyard of wrestling casualties courtesy of Vince McMahon. Well, TNA is still going as Impact Wrestling, but they're not posing any sort of threat (not that they ever really did).
Regardless of these promotions' outcomes, both TNA and WCW produced some top tier wrestling talent. So much so, the WWE had to get its hands on many of them. Today's WWE roster is filled with wrestlers that made their names in other promotions. Let's see who wrestled for rival promotions such as TNA, and yes, even WCW,
10 WCW: AJ Styles
Before he was Mr. TNA, The Phenomenal One had a very short stint in WCW in the company's dying days, showing up on Thunder. Teaming with Air Paris (we don't know, either), the tag team was known as Air Raid. They competed in a tournament to crown the inaugural WCW Cruiserweight Tag Team Champions, losing in the first round.
That's... basically it. Styles didn't really do much in WCW, leaving the company for the indies, finding his groove in ROH, and becoming one of the best wrestlers in the world in TNA.
9 TNA: Mickie James
While many fans might remember Mickie's more recent stint in TNA during the early 2010s, only hardcore fans will remember her previous run back in 2002 as Alexis Laree. She took part in the first ever weekly TNA PPV and had a few matches before officially joining Raven's stable at the time, The Gathering.
James would move on from TNA and make a name for herself in the WWE, but in 2010, the company decided to let her go. She returned to TNA, where she won the Knockouts title 3 times before once again returning to WWE.
8 WCW: Rey Mysterio
Rey Rey was a young lad when he joined WCW in 1996 after a brief stint in ECW. That's where his legend really took off, becoming the masked high-flyer most will say is the GOAT. From feuding with Chris Jericho, Dean Malenko and the nWo (shout-out to that epic dart throw!), to his epics with Eddie Guerrero, Rey Mysterio had captivated the wrestling world.
It wasn't all sunshine, though, as WCW had him unmask for some reason (a part often forgotten about his career), and he never really got the main event push he deserved.
7 TNA: R-Truth
Not only is R-Truth a former Total Nonstop Action employee (using his real name, Ron Killings), he's also the second ever NWA World Champion under the TNA banner, having beaten Ken Shamrock. Right before he joined, R-Truth had a quick but forgettable run in WWE as K-Kwik, a rapper who tagged with Road Dogg.
He spent a few years in TNA before returning to the 'E in 2008, where he has entertained fans with his hilarious antics, from Little Jimmy to the 24/7 European Television 7/11 Title shenanigans. Oh, that's what's up!
6 WCW: Triple H
The Game was being played in WCW long before Triple H was even a thing. Those golden locks belong to none other than Terra Ryzing (silly WCW with its ridiculous names and gimmicks). His name was soon changed to Jean-Paul Levesque (basically his real name), and he would adopt the snobby, wealthy person gimmick that started in WCW and continued in WWE as Hunter Hearst Helmsley.
It's crazy to think that during his time in WCW, Triple H actually competed at Starrcade in a losing effort to Alex Wright. He would also team up with William Regal, but that didn't last long as he signed with WWE in 1995.
5 TNA: EC3 & Drake Maverick
Oh, how far you've fallen ECIII - or should we say, EC3. No, he's no longer Ethan Carter the Third, and it's a shame too, because EC3 in TNA was an absolute star. Sure, he may not be the best in-ring performer, but with a great look and gimmick, and awesome promo skills, TNA saw his potential and made him World Heavyweight Champ. In WWE, he's an afterthought, used mostly as a jobber in filler segments.
His close friend Drake Maverick is doing a little bit better for himself, as his relentless pursuit for the 24/7 Championship has made him a fan-favorite. He was known as Rockstar Spud in TNA, both teaming and feuding with ECIII.
4 WCW: The Undertaker
The Phenom has always been super loyal to Vinny Mac, as The Undertaker and WWE are pretty much synonymous. However, with Paul E. Dangerously as his manager (i.e. Paul Heyman), The Undertaker wrestled for WCW for about a year between 1989-90 as "Mean Mark" Callous. He also formed a tag team called The Skyscrapers (replacing Sid Vicious as a member). McMahon came calling not long after.
A special shout-out to Taker's Brother of Destruction, Kane, who wrestled a single match in WCW. He lost to Sting, funnily enough.
3 TNA: Drew McIntyre
If it wasn't for his run in TNA, Drew McIntyre would not be where he is today. For the fans who remembers his earlier stint in WWE as "The Chosen One", well, he was anything but. He had no presence, was only passable in the ring, and his mic work left a lot to be desired (he did have an awesome theme song, though). He was eventually released after teaming with Jinder Mahal and Heath Slater in 3MB, but that was the best thing that could have happened to him.
During his time away, McIntyre wrestled for TNA and other promotions, mastering his craft, adjusting his look and moveset, and doing the impossible: finding that "IT" factor that led him back to the WWE.
2 WCW: The Big Show
Weeeelllll... well, he's been around for quite a bit, hasn't he? Big Show made his wrestling debut in 1995 as part of The Dungeon of Doom in WCW. Funny story: Big Show wanted to work for WWE and was in the process of applying, but Pat Paterson mistook Show for Kurrgan (another giant wrestler) and he was thus dismissed. Safe to say Vince wasn't happy with Paterson!
Everything worked out, though, as the Big Show did eventually find himself in the WWE in early 1999 after a fairly successful run in WCW, where he won the World Championship twice and the Tag Team titles 3 times.
1 TNA: The Hardys
Oh man, did these two create some magic in TNA. Sure, they both won the top prize in TNA and were involved in controversial, main event storylines, but this... this is the Hardys' greatest contribution to the wrestling world while under the TNA banner: THE FINAL DELETION!
The Broken Hardys and everything surrounding them was gold (including their Expedition of Gold!). Wrestling is supposed to be wacky and fun, and these guys delivered in spades. The Hardys were old news until they re-invented themselves with these characters, forcing the WWE to come calling.