What free things online should everyone take advantage of?

https://www.windy.com/ -Weather report with good graphics

https://10minutemail.com/10MinuteMail/index.html -Quick use and throw emails for signing up to shitty sites

https://pcpartpicker.com/ -If you're into pc building etc

https://opencourser.com/ -Search for courses online

Definitely free studying sessions - they helped me alot in exams.