A5 - Takes notes in your browser. Elegant & simple.
Knotable - Cut the noise out of busy email threads
Falcon for iOS - Writing notes made simple
Scrapbox - A new style of note-taking that lets you create, discuss, and learn together in one self-organizing space.
Chars - Unicode Symbols Keyboard for iOS
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.