Gollum

Category: Wikis & Knowledge Bases.

MIT🖥️ Self-hostable

XWiki

Category: Wikis & Knowledge Bases.

LGPL-2.1-or-later🖥️ Self-hostable

Zim

Category: Wikis & Knowledge Bases.

GPL-2.0-or-later☁️ Hosted only

TiddlyWiki

Category: Wikis & Knowledge Bases.

BSD-3-Clause🖥️ Self-hostable

Docmost

Category: Self-Hosted Apps, Wikis & Knowledge Bases.

AGPL-3.0🖥️ Self-hostable