Jamform - Collect form submissions without a server or database.
Flarum - Flarum is the next-generation forum software that makes online discussion fun. It's simple, fast, and free.
Discourse - Discourse is an open source discussion platform built for the next decade of the Internet.
Pairagraph - Clubhouse for the written word
OneUp - Schedule and automate posts on Facebook, Instagram, Twitter, Pinterest, LinkedIn, and Google My Business.
Jotform - Free Online Form Builder & Form Creator