Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Zukitwo - Zukitwo is a Gnome Shell and GTK theme that currently works on Gnome Shell 3.14 and the latest version of GTK.
Sketch - Professional digital design for Mac.
Materia - Materia is a development environment to build advanced mobile and web applications.
Invision - Prototyping and collaboration for design teams
Dark Language - Holistic language, editor, and infra for building backends