Qwirkle is a pattern game that fits perfectly in a standard age 5 or 6 curriculum. It is one of the most robust classroom games. The pieces are indestructible and if you lose a piece it doesn’t matter. The full game is too long for many age 5 and 6 students, so you should limit the number of turns for this age.
As well as playing the game, teachers can use the blocks as beautiful manipulatives to talk about patterns.