DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Pmwiki - PmWiki is a wiki-based system for collaborative creation and maintenance of websites.
Confluence - Confluence is content collaboration software that changes how modern teams work
MDwiki - Static single file CMS/Wiki done purely with client-side Javascript and HTML5.
Wiki.js - An open source, modern and powerful wiki app built on Node.js, Git, and Markdown.