Now UI Kit - A beautiful Bootstrap 4 UI kit. Yours free.
Placeit Unlimited - 12,000 smart design templates for $29
UX Toolkit for Figma - Create beautiful user flow charts, sitemaps and wireframes
Mockup Mark - Realistic apparel mockups for ecommerce, social & more
Landing UI Kit - Handcrafted UI components for landing pages
Merch by Amazon - Create, sell, and promote custom branded t-shirts