TreeSheets : Free Form Data Organizer (see strlen.com/treesheets)

Silicon Notes, a web-based personal knowledge base with few frills

A self-hostable bookmark-everything app (links, notes and images) with AI-based automatic tagging and full text search

Self-hostable private blogging

a file-based wiki engine and server featuring a productive source language, markdown, image generation, categories, templates, and revision tracking

Simiki is a simple wiki framework, written in Python.

Open source radio control system for almost anything.