George W. Bush 1994, 1998.
1994 in particular because he was running against an incumbent who was very popular and widely liked and respected even after she lost. Bush really was masterful then.
Ann Richards wasn't as widely popular as you think. She wouldn't have gotten elected in 1990 if the Republicans hadn't had Clayton Williams as the nominee (for the uninformed, during the course of the campaign, Williams (1) publicly declared that he hadn't paid income taxes in several years; (2) discussed visiting Mexican brothels as a young man; (3) said women who get raped should "lay back and enjoy it"). Combine that with the fact that the outgoing Republican governor had a scandal of his own that led him not to seek reelection and you have to wonder why Ann barely won by the skin of her teeth.
There was a broad swath of Texans who disliked her because she was pro-choice and liberal on other social issues, even if she was more or less a centrist in terms of fiscal policy. There is a joke that during the 1994 campaign, Richards staffers would put bumper stickers on their cars that said "I'm the Queer Who Ann Sent To Take Away Your Guns" and see if anyone tried to run them off the road.
