The "GO! Qube Mix & Match 5\" Block" set includes four dies in total, with dies 5 through 8 being specific shapes designed to work within the 5-inch finished block system.
These specific dies are:
Die 5: GO! Half Square Triangle-1 1/4" Finished Square (55572)
Die 6: GO! Square on Point-2 1/4" (1 3/4" Finished) (55573)
Die 7: GO! Parallelogram 45°-1 7/8" x 2 5/16" Sides (1 1/4" x 1 3/4" Finished) (55574)
Die 8: GO! Rectangle-1 3/4" x 3" (1 1/4" x 2 1/2" Finished) (55575)
Listing several individual GO! Qubes and happy to combine shipping, please reach out. Thanks!