DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
WackoWiki - WackoWiki is a light and easy to install multilingual Wiki-engine.
Wiki.js - An open source, modern and powerful wiki app built on Node.js, Git, and Markdown.
TiddlyWiki - a non-linear personal web notebook
XWiki - A powerful Open Source collaborative platform enhancing collaboration and communication.
Foswiki - Foswiki is the free and open source enterprise collaboration platform.