KWrite is a text editor by KDE, based on the Kate’s editor component.
Apostrophe
A clean and intuitive Markdown editor designed for those of you who love a distraction-free writing environment.
Howl
A general purpose, fast and lightweight editor with a keyboard-centric minimalistic user interface.
Abricotine
Abricotine is an open-source markdown editor built for desktop.
Gedit
While aiming at simplicity and ease of use, gedit is a powerful general purpose text editor.
Libre Office
LibreOffice is a powerful and free office suite, used by millions of people around the world.