Tonal - Machine learning digital gym + personal training built in
Select2 - Select2 offers customizable select box with support for searching, tagging, infinite scrolling, and many other used options.
Mirror - The mirror that's also an interactive home gym
Bootstrap - Simple and flexible HTML, CSS, and JS for popular UI components and interactions
MuscleWiki - Understand your body, simplify your workouts
Material UI - A CSS Framework and a Set of React Components that Implement Google's Material Design