Does anyone have a list of walk-on courts (that don’t require a reservation) in SF?

Any advise on how to generate power behind you serve/strokes? Thank you!

Here are some last chances for the enrollment calls. Sunday: 11am-12pm Monday: 8pm-9pm Thursday: 6:30pm-7:30pm https://calendly.com/bryan-cityracquetshop/play-tennis-challenge-enrollment-call

Please comment below and introduce yourself: 1️⃣ Where are you located? 2️⃣ Are you a player, coach, stringer, or shop owner? 3️⃣ What racquet and strings do you currently use? 4️⃣ What do you want to learn most about? I read every introduction and try to respond when I can.