Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
Flinto - The prototyping tool designers have been waiting for.
Figma Design Tokens - Making design tokens a single source of truth for Figma.
Base UI Sketch Framework - Huge set of everything you need to design and prototype
Ditto for Developers - Sync the latest copy edits from design to development
Glyphy - Copy & paste fancy fonts + cool symbols ☞✺✐™