htop - an interactive process viewer

Document viewer

GTKWave is a fully featured GTK+ based wave viewer for Unix and Win32 which reads LXT, LXT2, VZT, FST, and GHW files as well as standard Verilog VCD/EVCD files and allows their viewing.

Physically based rendering (PBR) for raylib

The minimalistic SQLite editor for non-programmers

DWARF debug info viewer using GTK+

an SVG image viewer for plan9

CHM file viewer for macOS

OpenGL program to interact with Minecraft Bocks

Image viewer/editor for RISC OS & desktop application library

Unofficial copy of GSview 5.0

A CSV file viewer implemented with ncurses

Another OBJ/MTL 3D models viewer

broadcom cfe configuration viewer and editor

Tiny X11 image viewer for QOI images.

Window Hierarchy and Properties Viewer

Tutorial for creating a Virtual Machine Viewer on Fedora with Spice-GTK

Simple picture viewer. Offers lossless rotation of JPEGs provided by libjpeg.

Independent ReactOS Clipbrd