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:

Behind the Scenes Minis: Piece of Work
17:48

E. Virgil Neal: Hypnotist, Fraudster, Tycoon, Part 2
41:22

E. Virgil Neal: Hypnotist, Fraudster, Tycoon - Part 1
35:28