Fludish Sketch UI Kit is high quality pack based on fluent design system, includes 50+ iOS screen templates designed in Sketch, 9 most popular categories (Sign In / Sign Up, Walkthroughs, Menu, E-commerce, Profile, Media, Statistics, Messages, Social)
Google recently released official Gmail Add-ons on G Suite Marketplace. Gmail Add-on Design Kit is a simple yet powerful design library for Sketch to speed and ease up your next Gmail Add-on design