Calligra Suite is an office and graphic art suite by KDE. It is available for desktop PCs, tablet computers, and smartphones. It contains applications for word processing, spreadsheets, presentation, vector graphics, and editing databases.
Pluma
Pluma is a text editor which supports most standard editor features. It also extends this basic functionality with other features not usually found in simple text editors.
QOwnNotes
Free open source plain-text file markdown note taking with Nextcloud / ownCloud integration
qpdftools
Qpdf Tools is an easy-to-use Qt interface for Ghostscript and Stapler, which makes it possible for normal users to manage their PDFs.
Hidrogen
Hydrogen is an advanced drum machine for GNU/Linux, Mac and Windows. It’s main goal is to bring professional yet simple and intuitive pattern-based drum programming.
Xournal ++
Xournal++ is a hand note taking software written in C++ with the target of flexibility, functionality and speed.
Notorious
Keyboard centric notes.
Curtail
Curtail (previously ImCompressor) is an useful image compressor, supporting PNG and JPEG file types.
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.