After Conor McGregor, eight other athletes who switched sports

BBC

Possibly the most successful multi-sport athlete in history, CB Fry's career began in the 1890s while at Oxford. There he won blues in cricket, football and athletics, and represented the university in rugby union. He went on to captain England in cricket, made one appearance for England in football, equalled the world long jump record and played rugby for Blackheath and Barbarians. He was also an acrobat. His party trick was to jump backwards from the floor onto a mantelpiece.