If live concerts that are free could be considered, Id have to go do a count cause I have 10+ of more than one band.
Umphrey's McGee and Phish are two that come to mind. Also, ANtibalas afrobeat orchestra I know I have 10+ of. And probably 20+ les claypool concerts (flying frog brigade, primus, Oysterhead, etc)
All free if you go to the places in my sig.