Swift Playgrounds - Learn serious code on your iPad in a seriously fun way
Icons-For-Free.com - Free icons sets, all sizes and popular formats, free licenses. Freebies icons sets
Bootstrap Zero - Open-source, free Bootstrap templates collection.
Photo Lab AI Artist - Hand-drawn-quality portraits from selfies drawn by AI Artist
Paper Signals by Google - Build-it-yourself objects that you control with your voice.
Flaticon - A database of free vector icons.