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.
Evernote
Evernote is a note-taking app helping you capture ideas and manage projects using a web clipper, files attachments, audio notes, and more.
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.