GTK topic
GTK (formerly GIMP ToolKit and GTK+) is a free software cross-platform widget toolkit for creating graphical user interfaces. It is licensed under the terms of the GNU Lesser General Public License, allowing both free and proprietary software to use it. It is one of the most popular toolkits for the Wayland and X11 windowing systems.
GameHub
All your games in one place
pdfarranger
Small python-gtk application, which helps the user to merge or split PDF documents and rotate, crop and rearrange their pages using an interactive and intuitive graphical interface.
nicotine-plus
Graphical client for the Soulseek peer-to-peer network
terminator
multiple GNOME terminals in one window
SwiftGtk
A Swift wrapper around gtk-3.x and gtk-4.x that is largely auto-generated from gobject-introspection
granite
Library that extends GTK with common widgets and utilities