Ghostscript 9.x PostScript interpreter, base part

https://www.cs.wisc.edu/~ghost/doc/GPL/index.htm

Ghostscript 9.x PostScript interpreter, X11 support

https://www.cs.wisc.edu/~ghost/doc/GPL/index.htm

A utility library that includes a wrapper for imlib2

http://www.linuxbrit.co.uk/giblib/

Tools and library routines for working with GIF images

https://sourceforge.net/projects/giflib/

Manipulates GIF images and animations

https://www.lcdf.org/gifsicle/

GNU Image Manipulation Program

https://www.gimp.org/

Gutenprint Printer Drivers

https://gimp-print.sourceforge.net/

C source code reformatter

https://www.gnu.org/software/indent/indent.html

GIO bindings not available in gtk-sharp

https://github.com/mono/gio-sharp

Distributed source code management tool (lite flavor)

https://git-scm.com/

Git extension for versioning large files

https://git-lfs.github.com/

Git "merge" driver for GNU style ChangeLog files

https://www.gnu.org/software/vc-changelog/

Util to keep branches in sync with remotes in git

https://github.com/ctubbsii/git-sync

Compact self-hosted Git service

https://gitea.io/en-US/

GitHub Enterprise Backup Utilities

https://github.com/github/backup-utils

GNOME Javascript binding

http://live.gnome.org/Gjs

Graphical frontend to su

http://www.gnu.org/non-gnu/gksu/

Program to create labels and business cards

http://snaught.com/glabels/

User interface builder for GTK+ 3

https://glade.gnome.org/

OpenGL spinning pocket watch demo and benchmark utility

GL Tubing and Extrusion Library

https://linas.org/gle/

OpenGL Extension Wrangler Library

https://glew.sourceforge.net/

Network-related giomodules for glib

Some useful routines of C programming (current stable version)

https://www.gtk.org/

C++ interfaces for glib2

https://www.gtkmm.org/

OpenGL image compositing library

http://freedesktop.org/Software/glitz

C++ mathematics library for software based on the OpenGL GLSL

https://glm.g-truc.net/

Library of C++ classes for flexible logging

https://github.com/google/glog

OpenGL and OpenGL ES shader front end and validator

https://www.khronos.org/opengles/sdk/tools/Reference-Compiler/

GNU version of 'make' utility

https://www.gnu.org/software/make/

Well-known mastermind game

http://gap.nongnu.org/gmastermind/

Library (written in C) for parsing and creating messages using MIME

http://spruce.sourceforge.net/gmime/

Library (written in C) for parsing and creating messages using MIME

http://spruce.sourceforge.net/gmime/

Library (written in C) for parsing and creating messages using MIME

https://spruce.sourceforge.net/gmime/

Well-known minesweeper game for GNUstep

https://gap.nongnu.org/gmines/

Generic matrix template library

https://getfem.org/gmm/

Free library for arbitrary precision arithmetic

https://gmplib.org/

Gecko Media Plugins API from mozilla-release

https://wiki.mozilla.org/GeckoMediaPlugins

GNU Flash movie player

http://www.gnu.org/software/gnash/

GNATS, the GNU Problem Report Management System

https://www.gnu.org/software/gnats/

Simple network library built upon Glib-2

https://www.gnetlibrary.org/

Glib wrapper around libarchives

https://gitlab.gnome.org/GNOME/gnome-autoar

Collection of backgrounds for GNOME

GNOME calculator tool

https://live.gnome.org/Gcalctool

Simple and beatiful calendar application for GNOME

https://wiki.gnome.org/Apps/Calendar/

Find and insert unusual characters for GNOME

Clocks for GNOME 3

https://wiki.gnome.org/Apps/Clocks

Session framework for the GNOME desktop to manage color profiles

https://git.gnome.org/browse/gnome-color-manager

Common automake macros for GNOME 3

https://www.gnome.org/

Contacts manager for gnome

https://wiki.gnome.org/Apps/Contacts