Joplin, the open source note-taking application

Obsidian is the private and flexible note‑taking app that adapts to the way you think.

A markdown-like text editor designed for writing novels and larger projects of many smaller plain text documents.

It is designed to be a simple text editor that allows for easy organisation of text files and notes, with a meta data syntax for comments, synopsis, and cross-referencing between files, and built on plain text files for robustness.

Zim is a notepad like desktop application that is inspired by the way people use wikis.

Yon is a little UI for knowledge designed to be used every day. Add your notes, write your diary, and connect thoughts with bidirectional links. Explore your text through an acme-inspired 2-column interface to dive deep or go wide and always find your way back. It's contained in a single html file with no dependency, so that you can open the lid and tweak any part of it and make it your own.

Text editor - Notes & ToDo (for Android)

Available on Mac, Windows and Linux

Pluma is the official text editor of the MATE desktop environment. While aiming at simplicity and ease of use, Pluma is a powerful general purpose text editor. It can be used to create and edit all sorts of text files.
Pluma features a flexible plugin system which can be used to dynamically add new advanced features to Pluma itself.

Kate is a modern text editor built on the KDE Frameworks and Qt.