QOwnNotes is an open-source plain-text note-taking application. The program supports markdown and includes a to-do list manager and many customization options.
Standard Notes
Standard Notes is an end-to-end encrypted notes-taking software that syncs with all your devices and has web and offline access.
Google Keep
Google Keeps is a simple notes organizer that lets you take voice notes, add images to notes, and create a to-do list.