Ellen Curtis Demorest and Ebeneezer Butterick are the two names most often invoked as the start of multi-sized patterns printed for home sewists. Once they proved it was a viable business, a lot of other offerings appeared.
Research:

SYMHC Classics: COINTELPRO 1
39:12

Behind the Scenes Minis: It's Not Unprecedented
16:46

The Rendition of Anthony Burns, Part 2
43:32