I run semi-continuous leagues at my location that usually have 14 players, but recently jumped to 24.
I also play in the Mile High Pinball League at Lyons Classic Pinball that has around 32 players.
Additionally, I started a team league in the Denver area that has 7 teams of 10 that travel around to each others' venues for matches each week. 38 additional players have played as substitutes so far this season. The team league has been better than I thought it would be at bringing in players who had not previously competed before...there is a lot of camaraderie, and attendance is highly incentivized.