Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Whether it's bookmarks or passwords, files or shopping lists...Turtl organizes it all and makes it easy to find later. Sync across your devices. Leave nothing behind.
Tomboy is a desktop note-taking application for Linux, Unix, Windows, and Mac OS X. Simple and easy to use, but with potential to help you organize the ideas and information you deal with every day.
Encryptic is an open-source note-taking application heavily focused on encryption. When you start writing, no one will know what you write except for you. We don’t know and we don’t want to know. That’s between you and your work.
Last update in Oct 2019, and last release in Jul 2019: https://github.com/encryptic-team/encryptic
KeyScrambler encrypts your keystrokes at the keyboard-driver level in the kernel as they enter the computer and decrypts the keystrokes at the destination application so that you see exactly the keys you've typed.
Crossnote is probably the world's first markdown notes reader & editor Progressive Web Application that works offline and supports syncing with arbitrary git repository right inside your browser.
Protects your private notes with a password. Notebook PEA is a self-decrypting archive, that will never store unencrypted text on your disk.
Write styled Markdown notes, sync across Mac, iPhone and iPad add to-dos and tags, export to a variety of formats and choose your favourite style from a variety of colourful themes.