If you are on Android I can recommend Orgzly. It ties in with Emacs' org-mode but is fully usable on its own with a sensible very convinient UI. It is open source and everything is saved in plain text that can optionally be kept in sync with Dropbox or WebDAV.
pydry|2 years ago
It's the first and only note taking app I liked.
LanternLight83|2 years ago