Ask HN: Boilerplates for quick prototyping of business ideas

I am unsure if this already exists in some shape or form but figured the best place to ask is HN :)

I wanted to figure out if there is boilerplate code available to test out ideas that are a little bit more evolved than launchrock pages or sign up templates. There are pretty easily available HTML templates but are there boilerplate templates that deal with certain well known functionalities - like for example a crowdfunding platform or a marketplace.

Besides scouring Github, is there something that people use reliably to prototype and see if a business idea has legs. Like FB Ad -> Landing Page ++ ?