No. 19 -- Martina Navratilova

Martina Navratilova was a professional tennis player and coach. Navratilova was world No. 1 for a total of 332 weeks in singles, and a record 237 weeks in doubles, making her the only player in history to have held the top spot in both singles and doubles for over 200 weeks. She won 18 Grand Slam singles titles, 31 major women's doubles titles (an all-time record), and 10 major mixed doubles titles, for a combined total of 59 major titles, marking the Open Era record for the most Grand Slam titles won by one player, male or female.