DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
MkDocs - Project documentation with Markdown.
Wiki.js - An open source, modern and powerful wiki app built on Node.js, Git, and Markdown.
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
TiddlyWiki - a non-linear personal web notebook
Docusaurus - Easy to maintain open source documentation websites