swagger.io - Swagger is an open source RESTapi Documentation Tool.
Algodoo - Algodoo is a 2D simulator freeware product designed as a physics learning tool. It was originally created by Emil Emerfeldt as part of his master’s thesis in 2008. Read more about Algodoo.
Link to QR - Free beautiful QR codes
SimPhy - Interactive 2D & 3D Physics simulation software
Slate API Docs Generator - Create beautiful, intelligent, responsive API documentation.
Physion - Physics Simulation Sandbox