Chameleon is a South African maker of many kinds of threads. These include pearl cotton in 8 and 12, floss, rayon, and several kinds of silk. In the US, The French Needles sells some of the silks. Although they are more geared to the free embroidery market, many of their threads will work for needlepoint. There are over 150 colors, with very few available across all threads. In addition they make four-color assortments called “Shades of Africa.”
Mary Corbet, of Needle n’Thread has an in-depth review of their stranded silk (i.e. sil floss). The article also has a great method for oening the skeins.