Daily Sudoku Puzzles - Free Online - 3 difficulty levels
#155
Sudoku expert:
https://dailybraintrainer.com/sudoku/expert-sudoku/daily-free-online-sudoku-game-expert-155/
Sudoku intermediate:
https://dailybraintrainer.com/sudoku/intermediate-sudoku/daily-free-online-sudoku-game-intermediate-155/
Sudoku easy:
https://dailybraintrainer.com/sudoku/easy-sudoku/daily-free-online-sudoku-game-easy-155/