MediaWiki
DokuWiki
TiddlyWiki
XWiki
Nuclino
Wiki.js
Confluence
BookStack
kdiff3
Beyond Compare
WinMerge
Meld
Araxis Merge
DiffMerge
P4Merge
Devart Code Compare
MediaWiki
kdiff3DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
Beyond Compare - Beyond Compare allows you to compare files and folders.
TiddlyWiki - a non-linear personal web notebook
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
XWiki - A powerful Open Source collaborative platform enhancing collaboration and communication.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.