Rotary replacement blades
Different size rulers
Books. Two of my favorites include:
Quilts! Quilts! Quilts!
The Quilter's Ultimate Visual Guide
Instructions on not leaving the mat in the sunlight and other storage tips.
Instructions on keeping her finger ON the ruler when she rotary cuts and to close the cutter when done! (My friend chopped her finger tip)
Instructions on how to get to quilter's cache, assorted quilting sites and of course, the QB.