helixnotes.com
HelixNotes is a local markdown note-taking app that keeps notes as plain .md files in a folder on the user's disk. It offers a rich editor with a source mode, a tasks view collecting checklist items, and a graph built from wiki links. It is free and open source under AGPL-3.0, with no account, and runs on Linux, Windows, macOS, Android, iPhone and iPad.
