The simplest way to keep notes … https://www.tromjaro.com/simplenote/
GTG
(GTG) is a personal tasks and TODO-list items organizer for the GNOME desktop environment … https://www.tromjaro.com/gtg/
Basket
multi-purpose note-taking application … https://www.tromjaro.com/basket/
FeatherNotes
Lightweight Qt5 Notes-Manager for Linux
… https://www.tromjaro.com/feathernotes/