digiKam - Professional Photo Management with the Power of Open Source
Unity - The multiplatform game creation tools for everyone.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Godot Engine - Feature-packed 2D and 3D open source game engine.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.