A cross-platform, reimplementation of Notepad++
A handwriting notetaking software with PDF annotation support
Hierarchical spreadsheet: a free-form data organizer
QOwnNotes is a plain-text file notepad and todo-list manager
A hierarchical note taking application
A minimalist note taking application
Cross-platform, parametric note-taking application
Smart Notes
Markdown note-taking app with a hierarchical note tree
Plain-text file notepad with markdown support and ownCloud integration
Light-weight Scintilla-based text editor with syntax highlighting
Semantic Note-taking tool for KDE