How neat! I don't collect them per se, but I have some spools of thread from when I was a little girl and my grandmother used to use and taught me with. Have a Talon color 330 hot pink color that I actually used recently and it's still in great shape, a Spun Dee 449.5, a Star mercerized from American Thread Co marked at 15 cents for the spool and a handful of JP Coats between 30 and 35 cents. They are probably worth not a lot, but they are worth millions to me!