List of readily available board games that build mathematical understanding.
Shared by the Phillips Brooks School through NCTM
Free online math themed picture books by Greg Tang.
More great math books being read aloud can be found at Math Read Alouds.
Make 10 game for Grades 1 and 2
Tic-Tac Toe for Grades 1 and 2
Counting Collections
Diffy Squares!
Over the Hill
First to 20 Math Game