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.

Going to a screen depending on a picker selection using states, variables and the 'Fire an items event' action

Showing a random image each time a button is pressed. Project was created using Variables and States

2 types of modals / popup examples

Netflix Desktop UI Sketch Resource Design: https://www.sketchappsources.com/free-source/3590-netflix-desktop-ui-sketch-freebie-resource.html

Using variables to change the opacity of items Design Downloaded from: https://www.sketchappsources.com/free-source/2567-chandelier-lighting-illustration-sketch-freebie-resource.html