Wargames
https://www.hackthebox.eu/
https://microcorruption.com/login
http://smashthestack.org/
http://pwnable.kr/
http://3564020356.org/deserve.htm
http://roothack.org/
https://holidayhackchallenge.com/2016/
http://www.hackertest.net/
https://canyouhack.us/
http://www.amanhardikar.com/mindmaps/ForensicChallenges.html
http://overthewire.org/wargames/
http://captf.com/practice-ctf/