The San Francisco Bay Area is one of the few places where life drawing models have a guild that supports them, advocates for them, and helps bring fair pay to them. Booking through the guild means you get a diverse set of fantastic models.
I sketched at one of their marathons recently and really enjoyed switching between models, switching up supplies and styles, and drawing for hours on end. Here are pieces from that session, all on letter sized sheets of paper.
More info on the Bay Area Models Guild here.
Or join them online some Thursday evening from 6pm to 8pm Pacific Time here.