Archivy is a self-hosted knowledge repository that allows you to safely preserve useful content that contributes to your own personal, searchable and extensible wiki.

A filebased wiki that uses markdown

Pepperminty Wiki is a complete wiki engine contained in a single file

BookStack is a simple, self-hosted, easy-to-use platform for organising and storing information.

TiddlyWiki is a complete interactive wiki in JavaScript. It can be used as a single HTML file in the browser or as a powerful Node.js application. It is highly customisable: the entire user interface is itself implemented in hackable WikiText.