Curtail (previously ImCompressor) is an useful image compressor, supporting PNG and JPEG file types.
MComix3
MComix is a user-friendly, customizable image viewer. It is specifically designed to handle comic books (both Western comics and manga) and supports a variety of container formats (including CBR, CBZ, CB7, CBT, LHA and PDF). MComix is a fork of Comix.
PageEdit
An ePub visual XHTML editor based on Sigil’s Deprecated BookView. It uses WebEngine instead of WebKit.
GdMap
GdMap is a tool which allows to visualize disk space. Ever wondered why your hard disk is full or what directory and files take up most of the space?
Synkron
With Synkron you can sync multiple folders at once.
Astrofox
Astrofox is a free, open-source motion graphics program that lets you turn your audio into custom, shareable videos. Combine text, images, animations and effects to create stunning, unique visuals. Then generate high-definition videos to share with your fans on social media.
Tupitube
TupiTube ( also known as Tupi 2D) is a free and open-source 2D animation software that is focused on usability for children, teenagers and amateur artists.
fihetsehana
Modern, minimal GUI app for libinput-gestures
CoolReader
Cross platform open source e-book reader.
Pika Backup
Simple backups based on borg