Xtend UI - Components
Dialog - Shoelace: A forward-thinking library of web components.
Fyne - go golang framework library for building UI for desktop and mobile
Bulma: a modern CSS framework based on Flexbox
Bulma is an open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.
GDevelop - Create games without programming - Open source HTML5 and native game creator
Create your own games with GDevelop: an open-source game creator. No programming skills are required! Quickly build and share your games on mobile (Android and iOS), desktop and on the web.
AribaWeb - More App, Way Less Code!
internna - Project Hosting on Google Code
List of Flash Gaming Engines — FlashRealtime.com
Golden T Studios - Golden T Game Engine (GTGE)
Golden T Game Engine (GTGE) is an advanced cross-platform game programming library written in Java language. GTGE library provides a complete routines for making 2D game from low level routines such as hardware accelerated 2D graphics, mouse and keyboard