Now UI Kit - A beautiful Bootstrap 4 UI kit. Yours free.
Startup Toolkit - Interactive how-to guides to launch your startup
UX Toolkit for Figma - Create beautiful user flow charts, sitemaps and wireframes
Techstars Entrepreneur's Toolkit - Online resource to help you learn about entrepreneurship
Landing UI Kit - Handcrafted UI components for landing pages
App Launch Checklist - Planning tool for launching your app successfully