Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
Encrypted Notepad - Encrypted Notepad is a very simple to use application providing state of the art...
GitJournal - Manage your Notes from any Git Repo.
Notebook PEA - Protects your private notes with a password.
Quillnote - Take beautiful markdown notes and stay organized with task lists.
Paranoia Text Encryption - Paranoia Text Encryption encrypts text according to a choice of strong algorithms.