Claudette Colbert in the infamous milk bath sequence of The Sign of the Cross (1932).
Mabel Normand in Mickey (1918). If Normand were alive to hear people say that silent movies are dull, she'd probably deck 'em. Not only was Normand a hilarious comic actor, but she also wrote, directed, and produced films as early as 1914. She was some kind of badass and a very funny lady. You can watch Mickey for free at the Internet Archive.