Like QuiltE, I have purchased project boxes (scrapbooking size) from Michael’s when they’ve been on sale 3/$10. I store blocks and notions in each. For example, I have one with my Jen Kingwell Longtime gone I am doing with a modern guild and I also have one that has an embroidery project, etc.
I also keep an extra sewing caddy/tote ready to take to a sewing group or class. It contains all the necessary sewing notions, seam ripper, scissors, machine needles, rotary cutter, small ruler, fabric marker, bobbins, neutral thread, etc.