PVC Pipe and bungie cords and clamps at my PQ1500s workstation to help manage large quilts during quilting.
Bungie cords, the door hinge on the door to the hallway, a heavy duty outdoor concert speaker stand and clamps at my PC420 workstation to help manage large art quilt and fiber arts projects during embellishment, quilting and free motion embroidery.
A tall candy tin and three paper cups squashed inside to hold the scissors, rotary cutters and elmers washable glue that I keep in the studio where my large cutting table stays.
The long skinny board that was the keyboard holder for my computer desk until the sliders broke, is now covered in batting and silver ironing fabric, making a nice long ironing board that I can easily move from place to place as needed, right now it's on the table beside my PQ1500s, but it often gets used on top of my large cutting table for ironing large quilt tops.
There's probably lots of other things, but those come to mind right now.
Rob