Glimmer - Fast and light-weight UI components for the web
Unity - The multiplatform game creation tools for everyone.
Preact.js - Preact is a fast 3kB alternative to React with the same modern API. Components & Virtual DOM.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Svelte - Cybernetically enhanced web apps
Blender - Blender is the open source, cross platform suite of tools for 3D creation.