Well, R-Truth, Christian, Goldust and CM Punk have all worked for TNA. But IMO the only one who really was "made" there was R-Truth. Plus Low-ki is the only other one I can think have that was a big time player in TNA who then went to WWE. I'm sure they may be someone I have missed.
You did miss a guy or two, man, but I want to touch upon a thing or two first.
R-Truth had a solid run with WWE prior to going to TNA (K-Kwik). While it's true that he became a world champ with TNA, which supposedly "made" his career, it was during TNA's formative period when they had very little "real" star power to work with. Hardly anyone was watching TNA during this period.
Matt Morgan also worked in WWE prior to becoming a part of TNA.
Now I'll mention a couple successful TNA guys who failed miserably in WWE.
1. Chris Harris. Dude was half of TNA's most successful tagteam prior to coming to WWE as Braydon (can't remember his last name). The signing of Harris could very well be an all time top 10 bust.
2. Monty Brown. This guy was a HUGE part of TNA in their early years and his run with WWE was beyond pitiful.
3. Mickey James. She briefly worked in TNA prior to being hired by WWE as well. I don't know if she was successful at all, because I never actually watched her work with TNA, but I know she was there. For how long, I don't know.
4. Lance Hoyt/Vance Archer. One could make an argument that he was at least moderately successful in TNA. The tag team he was part of did get tv time regularly for quite some time, and they even had some nice arm candy (Christy Hemme...who was aslo a WWE discovery).
Gail Kim is another worker who appeared in TNA for quite a while, and while she hasn't become champion since her return to WWE, she does get a little tv time. That's all 99% of the divas really deserve to be completely honest.
I'm not really trying to nitpick anything you said. I just thought I'd mention these names in case you had forgotten about their TNA past, or simply didn't know they had a past with TNA.