Not your typical Quilt supply:
A carpenters square about 2 feet long on one side and 18" on the other -- a flat metal one that will not flex, like some plastic ones. It is invaluable for squaring things up, and you can use it with your rotary cutter.
A long metal rule - 5' long for measuring and marking, etc.
Sandpaper on the back of your quilt pattern to hold fabric while marking.
At the office supply store -- sharpie pens, graph paper, water soluble glue sticks, tracing paper, colored pencils, square and round drafting templates.
Check at art supply stores for templates with different size circles - great for applique, also water color pencils for marking quilt tops.
Ice cream plastic buckets (the 1 gallon size) make wonderful wastebaskets, that can sit anywhere - especially on your cutting table.
PVC pipe from the hardware store to raise the legs of cutting tables.
Magazine file boxes to keep all your magazines in order, letter holders to hang on the wall to hold current or about to be current patterns and projects. Fishing tackle box to hold all your tools also, makeup cases are great for tools and small items.
Largest size zippered plastic bags to store fabric, organize sewing notions, pieces for blocks, finished blocks, etc. Cigar boxes, just wonderful for everything from storing pencils, needles, samples, tools, cut pieces for hand piecing.
Pizza boxes (clean ones) work great for organizing UFOs, blocks, pieces for blocks. etc.
Large refrigerator magnet for collecting pins and needles and keeping them in one place
Zip lock bags of all sizes for templates, pieces, instructions - everything you need sorted into baggies.
Flat wooden pant hangers for holding mats, or seasonal wall hangings when not in use
Shoeboxes for scraps sorted by color or size.
Remember, though, these storage ideas are temporary storage--be careful about putting finished quilts in plastic bags or card/wood boxes--line it with archival paper first.
One of the best ways to store a quilt is on an extra bed. Keeping the quilt flat will eliminate creases and wear on folds. Simply cover the quilt with a clean sheet or bedspread.
If storing it flat is not an option, store the quilt in a cotton or muslin bag or in an acid-free box. Do not store in the attic or basement where moisture and temperature levels will fluctuate. Before you fold the quilt, use acid-free tissue paper as padding to prevent sharp creases. You can also roll your quilt around an acid-free tube and slip it in a cotton bag.
If you are storing your quilt in a wooden box or dresser, wrap it in the acid-free tissue to avoid contact with the wood. Oils and acids in the wood can cause spotting and damage. Once a year, bring your quilt out of storage to air and to check for damage. Refolding will also prevent permanent creases and damage.
Use empty prescription pill bottles to hold thread for a take-along project. These bottles come in several sizes and can be purchased from your local pharmacy for very little if you don't have any on hand. Use a hot needle and poke several holes around the top of the plastic. Fill several bobbins with the colors you are using for your project. Place the bobbins in the pill bottle and thread each through one of the holes. Place the lid on the bottle and secure the dangling threads with a rubber band (the ones that come with vegetables for a perfect fit). You can pull down the thread you are using. You can also put just one spool of thread in a pill bottle if you are working with one color, or if you are quilting.
Here's some more info on folding your quilt: When folding a quilt, use crumpled sheets of archival tissue in long "roll" shapes in fold areas of the quilt to support the fabrics and avoid sharp creasing. If you pack away a quilt with half and quarter folds, you should re-fold them in thirds to redistribute stress on the quilt. Refolding every 6 - 12 months is recommended.