Adobe XD - Adobe XD is an all-in-one UX/UI solution for designing websites, mobile apps and more.
INSTAD.IO - Automagically converts vector images into sketchy style
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Base UI Sketch Framework - Huge set of everything you need to design and prototype
Sketch 42 - Now with export presets, touch bar integration, and more
Sketch Extensions - An official collection of Sketch extensions & plugins