QOwnNotes
QOwnNotes is a open source (GPL) plain-text file notepad with markdown support and todo list manager for GNU/Linux, Mac OS X and Windows, that (optionally) works together with the notes application of ownCloud (or Nextcloud). So you are able to write down your thoughts with QOwnNotes and edit or search for them later from your mobile device (like with CloudNotes) or the ownCloud web-service. The notes are stored as plain text files and you can sync them with your ownCloud sync client. Of course other software, like Dropbox, Syncthing, Seafile or BitTorrent Sync can be used too.