tl;dr, check these sites:
https://www.wikimatrix.org
http://wiki.c2.com/?TopTenWikiEngines <- origin of the word "wiki" ( http://wiki.c2.com/?WikiWikiWeb )
Having setup the whole Atlassian on-prem SSO suite of apps on Linux with Git and LDAP talking to AD on Windows, it depends on your needs, as there are a variety of different wiki/collaboration solutions with different capabilities. I've also used these:
- Dokuwiki (very simple, text file-based)
- Mediawiki (LAMP / database-backed)
- SharePoint (MS $$)
- Quip
Others to look at (including sometimes CMSes)
- OneNote
- Liferay
- Drupal
- Statamic
- WordPress
Also, Confluence has tons of plugins for customization and can be made to be fast with proper configuration.