DriveThruRPG
Every title in PDF, including the pay-what-you-want ones.
Lulu
Print on demand for the books that exist on paper.
Kickstarter
Live campaigns and late backing, when there’s one running.
TeePublic
Shirts, stickers and other things you can wear.
A note on print
Offset print runs are subject to availability. When a title has sold out of its print run, print on demand through Lulu is the way to get a physical copy.
Gaming accessories
Custom dice and other things to make the table better are coming.