Fun Math Games:
https://junilearning.com/blog/guide/best-free-math-games-for-kids/

https://www.weareteachers.com/the-best-online-interactive-math-games-for-every-grade-level/#elementary

Khan Academy 

Number Sense Games:

https://www.symbaloo.com/mix/mathnumbersensegames?lang=EN

Number Sense and strategy Games:

A link to multiple classic card and dice games:

https://cardgames.io/

Nim: 

 https://www.archimedes-lab.org/game_nim/play_nim_game.html

Farkle:

https://cardgames.io/farkle/

Multiplication Facts Practice:

https://www.mathplayground.com/index_multiplication_division.html

https://www.turtlediary.com/games/multiplication.html

https://www.multiplication.com/games/all-games

https://www.mathplayground.com/math_lines_multiplication.html

Guess My Number:

https://www.funbrain.com/games/guess-the-number

Interactive 100's chart:

https://toytheater.com/hundreds-chart/

Khan Academy