A simple, fast, no-nonsense to-do (task) list.
Balsa
Balsa is an e-mail client for GNOME, highly configurable and incorporating all the features you would expect in a robust mail client.
Ferdi
Ferdi is a messaging browser that allows you to combine your favorite messaging services into one application.
KPhotoAlbum
If you have hundreds or even thousands of images on your hard drive, it becomes impossible to remember the story behind every single image or the names of the persons photographed. KPhotoAlbum was created to help you describe your images and then search the big pile of pictures quickly and efficiently.
Knowte
Cross platform note taking application
FeatherNotes
Lightweight Qt5 Notes-Manager for Linux
Polari
IRC client which enables you to chat with people around world through large chatrooms or via private messaging.
Jami
Share, freely and privately. Decentralized messenger with VOIP.
Fractal
Fractal is a Matrix messaging app for GNOME written in Rust. Its interface is optimized for collaboration in large groups, such as free software projects.
Claws Mail
Claws Mail is an email client (and news reader), based on GTK+, featuring
Quick response
Graceful, and sophisticated interface
Easy configuration, intuitive operation
Abundant features
Extensibility
Robustness and stability