Could argue Deonte Burton and Solomon Young. Shayok was a completely different player under Prohm than he was under Tony Bennett, but that's likely more due to the system.
If you simply apply a team scoring avg. adjustment Shayok scores about 11 ppg. You can say he was a better fit in ISU's system, but when Shayok decided to go to ISU, nobody would've predicted he'd score 19 ppg and be an All-American. He was night and day better from his UVa days, and it isn't simply because ISU played faster.
Thomas made a huge jump from So. to Jr. He become a really good two-way player. Nader was logging DNPs prior to Prohm, then went on to the NBA. Over 2 seasons at Marquette Burton averaged 6.5 ppg.
How much you want to attribute to Prohm or the players themselves improving with experience and time is up to you. But all of these players made step-change improvements under Prohm vs. their pre-Prohm careers.
There were certainly players that stagnated and even some that regressed, too. This season has been a massive failure, but I don't think we need to revise history and say that guys haven't gotten better under Prohm. I do think mostly what you see with the guys that made big jumps is they are score-first guys with guard skills and length that need the ball in their hands, particularly Shayok, Nader, and Burton. I think this is Prohm's sweetspot, and he really didn't have that this year. As great as Tyrese is, he needs a roster of shooters and pick and roll finishers around him to be at his best. I think Wigginton or THT could've fit that bill well.
Ultimately it's up to the coach to either ensure the roster fits his style or adjust his style. I'm hoping Bolton can make a big jump with both finishing more consistently, improving his reads and passing. Otherwise I think expecting a guy like Johnson or Blackwell to step in and fill that role seems to be asking too much.