Are there any players who have won an NCAA basketball championship while playing for two different teams?
No player has ever won NCAA basketball championships with multiple teams.
The player who came closest to achieving this is Bob Bender. He was on the undefeated 1976 Indiana team that won the national championship, and he was also on the 1978 Duke team that lost to Kentucky in the title game.
Wikipedia says Bob Bender is the only college basketball player to reach the NCAA championship game for two different teams:
Bender has the distinction of being the only individual to play on two different teams in two different NCAA Championship games.