Better late than never, so here's the season finale dates for selected game shows:
WOF: June 13 (season completed)
J!: August 1
WWTBAM!: May 23 (Cedric's first - and only - season completed)
Let's Ask America: May 23 (season completed)
Family Feud: May 21 (season completed)
Win, Lose or Draw: May 21 (season completed)
LMAD and TPIR: unknown, to the best of my knowledge
Any others, please feel free to contribute
Brian