Open Source Note Taking Apps

Joplin Windows, macOS, Android, iOS, Linux, Web Extension
Simplenote Windows, macOS, Linux, Android, iOS, Web
Standard Notes Windows, macOS, Linux, Android, iOS, Web
Turtl Windows, macOS, Linux, Android, Web Extension
Laverna Windows, macOS, Linux, Web
Takenote A web-based notes app for developers. (Demo only)
Xournal Windows

Open Source Image Viewers & Editors

Nomacs Image viewer
ImageGlass Image viewer
Photoflare Image viewer
IrfanView Image viewer
JPEGView Image viewer
PhotoQT Image viewer
QuickViewerImage viewer
LightGalleryImage viewer
Phovito Image viewer
GIMP Image Editor
Darktable Image Editor

Open Source Video Editors

Shotcut Video Editor
Kdenlive Video Editor
OpenShot Video Editor
Olive Video Editor
Flowblade Video Editor
Natron Video Editor
PitiviVideo Editor
AvidemuxVideo Editor