Preact.js - Preact is a fast 3kB alternative to React with the same modern API. Components & Virtual DOM.
Kommunity - Explore communities that share your passion with millions of people
Inferno - An extremely fast React-like javascript library for building modern user interfaces.
Facebook Groups - This app gives you a dedicated space for you and your groups
Glimmer - Fast and light-weight UI components for the web
MemberSpace - MemberSpace lets users create online course, training program, or other business idea inside existing Squarespace website.