Nymo is one of the most popular and easy to find nylon beading threads for seed beads.
It is a nylon monochord, which means it is a single bonded strand, not several twisted together. This is helpful in beadwork, especially when you have to remove stitches - it won't untwist and separate.
Size D is a commonly used size with size 8, 11, and 15 seed beads.
100% cotton for crochet and needlework 757 metres Made in Spain
100% cotton for crochet and needlework 505 metres Made in Spain