Good First Issue - Make your first open-source contribution
Hackr.io - There are tons of online programming courses and tutorials, but it's never easy to find the best one. Try Hackr.io to find the best online courses submitted & voted by the programming community.
Udemy - Online Courses - Learn Anything, On Your Schedule
codeonthecob.com - A better way to practice coding
GitSheet - A dead simple Git cheat sheet.
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.