Burgess Meredith
Burgess Meredith played the Joker in the 1950's Batman film. He was also a popular character in The Twilight Zone. During the red scare, he was blacklisted over his possible connections to communists. He was never involved with the movement and luckily at enough proof to clear his name.
Lucille Ball
Hollywood would not be what it is today without Lucille Ball. That didn't keep her name clear from the red scare, though. She was asked to testify in front of the HUAC but was never arrested. She was still under suspicion of having communist ties, but honestly, she was way too busy to get caught up in that!