Bootstrap Zero - Open-source, free Bootstrap templates collection.
Sketch Repo - Collection of resources for anyone who uses Sketch
Bootstrap Magic - Create your Bootstrap 4.0 themes easily with magic
Frames for Sketch - Create awesome websites & apps using powerful design system
Material Design for Bootstrap 4 - Powerful and free UI KIT for the newest Bootstrap 4 and Material Design
Confetti for Adobe XD - Generate gorgeous confetti patterns in 1 click