I made this Lightless Silk farming guide to help out players who want to farm the cloths instead of buying them from the Auction House. I traveled around Shadowlands to search for places with a high density of mobs which I can kill and drop Lightless Silk. Below you will find a list of places I think are the best for farming Lightless Silk.
Lightless Silk is dropped by every mob that can drop Shrouded Cloth, but it has a lot lower drop rate.
Tailors will get much more cloth than non-Tailors because of Shadowlands Cloth Scavenging, even if their Shadowlands Tailoring skill is 1. Don't expect a lot of Lightless Silk if you farm without Tailoring.
Keep in mind! Several people can tag the same mob and still get loot. So, even if someone is already killing your mobs, you can just help him and you can loot it too.
Revendreth - Archivam
You can farm a lot of Lightless Silk from Beleaguered Excavators, Excavation Enforcers, Nefarious Thugs, and Nefarious Collectors at Archivam in Revendreth. They are really close to each other, so you can make big pulls and AoE them down. The respawn rate is fast enough that you should never run out of mobs.
The only downside is that the Beleaguered Excavators are neutral so you can't pull them with your mount.
You can sell your stuff to Nourman when your bags are full.
Ardenweald - Tirna Noch
Blighted Fadeblades and Masked Soulsplitters respawn really fast around the marked area. They hit a bit harder than the previous mobs, but if you have good gear you can easily pull 8-10 together with your mount.