Slidesgo - An extensive catalog of free Google Slides themes and PowerPoint templates.
Unity - The multiplatform game creation tools for everyone.
SlideModel.com - Create attractive presentations with our professional PowerPoint templates, slide designs, and themes. Use our PPT templates and slide designs to give unique appearance to your presentation.
Godot Engine - Feature-packed 2D and 3D open source game engine.
SlideTeam - Transform rough sketches, notes into professional PowerPoint presentations.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.