Overleaf

Knowledge base that works with a SQLite db file.

Note taking application with markdown editor and encryption support for mobile and desktop platforms. Runs client-side and syncs through a self hosted Nextcloud instance or similar (alternative to Evernote).

Cross-platform hierarchical note taking application with focus on building large personal knowledge bases (fork of Trilium Notes).

Collaborative note taking, wiki and documentation platform that scales.

A personal note tool with AI features.

Diagram software for making flowcharts, process diagrams, org charts, UML, ER and network diagrams.