with 500 squares you could a number of different patterns.
9p; D9p, sudoku, alternate 4 patch, or alternate 9 patch.
variation on a coin coin quilt, sew rows of the blocks and add strips of fabrics between the rows of blocks. The list goes on...
another option is if you do applique, piece blocks together as a foundation for the applique.
take some graph paper and doodle, there are dozens of options, you don't have to make them all at once either.