Notepad

TagSpaces is an offline, open source, document manager with tagging support

An offline-first, secure, private notepad.

Joplin - the privacy-focused note taking app with sync capabilities for Windows, macOS, Linux, Android and iOS.

draw.io is a JavaScript, client-side editor for general diagramming.

Simple and visually-pleasing Pomodoro timer

Ambient sounds for focus and calm.