Heavy Duty 1" contractor retractable tape measure that locks... put that puppy out and it's not going anywhere while you measure.
Canned goods... put on my 6" wide ruler while cutting so it doesn't move on me...doesn't matter how careful I am, if I don't have it weighted down, it will move.
Tupperware orange peeler...same as a stiletto for me
Blue painter's tape... use if for so many things...holding pattern up on cabinet while I cut things out, marking rows on quilts while arranging them on design wall, embroidery tack downs, etc etc etc
binder clips -- yep cheaper than the fancy dancy ones
flashlight -- look under the long arm at my stitches
Baggies --- keeps things grouped together
artist scrapbooking clear plastic boxes from Michaels -- 14 1/2 x 14/ 1/2 x 4 high --- wonderful for putting finished blocks in during swaps and for grouping project fabric together