Any sport you have the ability to profit in :wink:

Sport markets that are less efficient would be easier though. Tennis & golf simply because of the size of the fields. Those 2 sports would obviously take a huge amount of work though.

Aussie sports are generally decent. Less efficient than the major US sports.

US college sports.

Don't know anything about greyhounds but I think it'd be easier to beat than the horses.

Start off with a sport you know prett well though.