Tomdroid is described as 'The aim of this project is to bring the same goodness to the Android platform. The goal is to be file format compatible and be able to sync notes with tomboy. Of course, keeping a great UI adapted to the mobile context is also a goal of this project' and is an app in the Backup & Sync category. There are more than 50 alternatives to Tomdroid for a variety of platforms, including Windows, Android, iPhone, Mac and Online / Web-based. The best alternative is Joplin, which is both free and Open Source. Other great apps like Tomdroid are Standard Notes (Freemium, Open Source), Google Keep (Free), Microsoft OneNote (Freemium) and Evernote (Freemium).
NoteAway is the simplest, most convenient way to take quick notes on OS X. NoteAway has lots of powerful features for free, like iCloud syncing, rich text, attachments, simple import/export, and a variety of customizable options.
This program is a structured notetaking application based on GTK+ 3. Write your notes in instantly-formatted Markdown, organise them in a tree of folders that can be instantly navigated from within the program, and add hand-drawn notes by mouse, touchscreen or digitiser.
MixNote is a mobile note taking app, like a memo pad or notepad. Take note of every deserved thing, with text, ToDo, voice and picture. You can take notes, write memos, create to-do list, record voice and add pictures in MixNote. Make your notes more varied and interesting.