List of Ongoing Contest: https://clist.by/#
Profile having records of CP accounts of different websites: https://www.stopstalk.com/ (great for getting solutions of every questions)
Codeforces Visualizer: https://cfviz.netlify.app/index.html
Competitive Coding Platforms:
- https://codeforces.com/
- https://atcoder.jp/
- https://www.codechef.com/
- https://www.spoj.com/
- https://www.hackerrank.com/
Interview Based: