I made this Heavy Callous Hide farming guide to help out players who want to farm the leathers instead of buying them from the Auction House. I traveled around the Shadowlands to search for places with a high density of mobs which I can kill and drop Heavy Callous Hide. Below you will find a list of places I think are the best for farming Heavy Callous Hide.
All skinnable mobs can drop the 5 new skinning materials, so you will basically farm the same mobs for every leather.
Heavy Callous Hide is a rare leather that you can skin from any skinnable mobs in the new Shadowlands zones. It has a really low drop rate, so don't expect much.
Heavy Callous Hide
Don't forget to enchant your gloves with Enchant Gloves - Shadowlands Gathering! This enchant brings skinning time down from 1.5 seconds to 0.5 seconds. (works with herbalism and mining too)
Bastion - 1
The best way to get a lot of Heavy Callous Hide is by farming Anima-Starved Cloudfeather and Anima-Starved Wyrm inside Kala's Den in Bastion. There are always at least 4-5 mobs up inside the cave, and a new one will instantly spawn if their numbers would go below that. Extremely good farming place, it actually might get nerfed.
Make sure that you also kill the Anima-Starved Cloudfeather that sometimes patrols back and forth towards the cave's entrance. (it will force more mob spawns)
Bastion - 2
Farming Languishing Etherwyrms and Starved Etherwyrms around the marked area is also a great way to get a lot of leathers. They are needed in one of the starter quests in Bastion, so this area will be pretty busy at the start of the expansion. (which can be good if no one is skinning them)
You can find a lot of Gorm Raveners at Northwest of Glitterfal Basin. They respawn extremely fast, and you can always pull at least 3 of them together. They hardly do any damage and they have low armor.
Maldraxxus - 1
Maldraxxus - 2
Kill Virulent Pests around the marked area. They are a bit spread apart, but the respawn rate is fast, you will never run out of mobs to kill.