Rainbow UI Kit is a web app design tool that offers a colorful Bootstrap 4 UI kit for landing pages. Files in the UI design pack include Sketch, Slim & html, CSS & SCSS, Config for Codekit, and Config for Prepros. Rainbow UI Kit currently sells for $70 per kit download.
The product was created by cofounder Ciocanel Razvan, Stafie Anatolie, and Alin Spiridon.