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

• Kenkoooo

For all sites

• Vjudge

EDIT1: DATE(11-07-2021)

For codechef

• Codechef-Practicechef

For Problems(codeforces)

• Problem-Forces