Website Based on codeforces (By users)
- CF-predictor
- Codehunt
- Contest-mania
- Codedigger
- Algoshots
- By-User
- Codedrills
- Codeforces-Visualizer
- Compare(Cf statistics)
- Codeforced
- Upsolver
- Competitive
- GYM-Solver
- Comments-Finder
- Extension(Practice tracker)
- Upsolver
- Workspace
- Yet another practice website
- Random-problem
- StopStalk
- Team DashBoard
- GameOfCodes
- LockOut Match between two players
Atcode Based Sites
For all sites
EDIT1: DATE(11-07-2021)
For codechef
For Problems(codeforces)
What is vjudge used for?
Making mashups of problems from different OJs, and some contests are also hosted there.