Undum : A client side framework for hypertext interactive fiction games
Ionic : The beautiful, open source front-end SDK for developing hybrid mobile apps with HTML5.
Pure : A set of small, responsive CSS modules that you can use in every web project.
YAML Builder : A tool for visual layout development of YAML based CSS layouts
LÖVE is a framework for making 2D games in the Lua programming language. LÖVE is totally free, and can be used in anything from friendly open-source hobby projects, to evil, closed-source commercial ones.