I used part of the "Laundry App UI Kit Sketch Resource" design that was designed by Satheesh Kumar at: https://www.sketchappsources.com/free-source/3397-laundry-app-ui-kit-sketch-freebie-resource.html to create a quick prototype

This prototype showcases a new Proto.io feature called Gradients, it’s a new way to create and animate gradients straight in Proto.io. You can now make your UI pop with vibrant linear or radial colors, and bring to life with beautiful animations.

Basic To Do prototype based on: https://www.sketchappsources.com/free-source/3625-basic-to-do-app-design-sketch-freebie-resource.html

Tinder UI cards

Hit Refresh icon to see a loading animation for bringing new email. Swipe left on the top latest email to delete. (Inspired from http://www.beautifulinterfaces.com/item/114-covert-inbox)

Smart Menu is a smartphone app that allows students to create their own health goals and uses those goals to find healthy restaurants and food options nearby. Smart Menu collates menu data from the restaurants and individual reviews from students. This data plus the health goals allow the app to help students find healthy eating options.

An as close as possible copy of the IFTTT onboarding experience. This prototype is also made in 4 other tools (Pixate, Origami, Framer & Form) to compare the differences between them. More info: http://medium.com/sketch-app-sources/five-app-prototyping-tools-compared-form-framer-origami-pixate-proto-io-c2acc9062c61 Original app: http://appstore.com/IFbyIFTTT