What's this trend of selling boilerplates all of a sudden?

Low effort, considerable results, benefits for both sides I suppose.

can you elaborate with examples? Im not sure ive come across these boilerplates (i mean there's a lot of boilerplate stuff potentially out there - what specifically are you referring to?)

I think it began with Marc Louvion and its React boilerplate Ship Fast. He made an impressive 30k its first month. He paved the way for the boilerplate Eldorado.