I am lefty myself, I use Logitech g903, its hard being lefty in righty world lol
I recommend Logitech g903 Ambidextrous I believe Logitech G PRO is Ambidextrous
I do know G Pro League of Legends Edition is Ambidextrous for $49.99 if color doesn't bother you.
Check out the pwnage ambi mouse. Ive been using it a month and like it. Its similar to Logitech G Pro but less of a hump. Not to many options out there