If you haven’t spent much time on OpenSFHistory.org, remedy that immediately! It’s a fantastic collection of historic photos from a private collector that the Western Neighborhoods Project is hard at work digitizing, and sharing with the world.
Here are a few gems from their latest update:

Golden Gate Park circa 1925. Zebra Team with man and cart. OpenSFHistory / wnp14.4531.jpg

Ocean Beach circa 1960. Unknown man at Ocean Beach – Esplande (Bernal Heights man). OpenSFHistory / wnp14.4569.jpg

Golden Gate Park circa 1910. Father and 3 sons, Golden Gate Park Pool of Enchantment? OpenSFHistory / wnp14.4577.jpg