Cool ideas of websites you'd like to see built?

I've always wanted a website (I'd even pay for this) with condensed guidelines for interfaces based on existing research with citations. Say I was tasked with making a feed-based UI at work and wanted to quickly learn the best practices on how to do that with links to the "why", where would I even go today?

It feels like researchers do all this work and too often all folks end up doing in an office is "Go look at the market leaders and copy what they did." Even though the market leaders may not have always followed the research for any number of reasons, many of which may be product specific.

I did mocks for this at some point, just couldn't find time to do all the reading necessary to make the content (hence it probably needing to be a paid service).

Honestly, I'd just like a product hunt kind of thing, but maybe not for digital stuff. If I wanted to buy say, a mattress, I don't want to go through all these SEOed "reviews" on Google.

A way to see all the people on Twitter who live in your city (like a “search by location in bio” feature)