I bought the first pack of ~3 or 4, then discovered that there are lots of braided whatevers that haven't been converted to loops. The last ones that I made were from a nylon adjusting cord from window blinds, those are for my Steelhead and Hybrid Striped Bass lines. Others were from braided running line.
I made a puller (like a bobbin threader, only longer) out of a banjo string (G) to insert "up the gut' to snatch the tag end prior to pulling through to form the loop.
Cheers,
R