DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
Turtl - The secure, collaborative notebook
Wiki.js - An open source, modern and powerful wiki app built on Node.js, Git, and Markdown.
Tomboy - Apps/Tomboy - GNOME Wiki!
TiddlyWiki - a non-linear personal web notebook
Omni Notes - Note taking open-source application aimed to have both a simple interface but keeping smart behavior