Butterfly
Powerful, minimalistic, cross-platform, opensource note-taking appAGPL-3.0-only
Linwood Butterfly Nightly
Powerful, minimalistic, cross-platform, opensource note-taking appAGPL-3.0-only
Threema Libre
Secure and private messagingAGPL-3.0-only
Notesnook - Private notes app
A fully open source & end-to-end encrypted note taking appGPL-3.0-only
LibreOffice & OpenOffice document reader | ODF
Document reader & file editor for Libreoffice & OpenOffice | ODF: ODT, ODS +moreGPL-3.0-or-later