Stonehide Leather

Keep in mind! In Legion, several people can tag the same mob and still get loot. So, if someone tagged your mob but he didn't loot the corpse, you can't skin the mob.
Most Legion mobs scale to your level, so these places are good for players between level 100 and 110.
If you are honored with the Highmountain Tribe, you should get the [Boon of the Butcher] enchant from Ransa Greyfeather at Thunder Totem. It allows you to sometimes loot [Butchered Meat] which can contain extra Leathers and Meats.
SuramarThe respawn rate of Suramar Snarlers is really fast. You will never run out of them. The best way to farm here is to pull 7-8 together with your mount, then AoE them down.
You will probably cap on Ancient Mana, so you will have to go to Suramar City and spend your mana on something. You will find vendors all around the city, but you can't speak to them until you progress a bit in the story line and get your disguise.

StormheimYou can find a lot of Saberfang Worg at the marked area.

AzsunaThe Llothien Prowlers are a bit spread apart at this place, so the best way to farm here is to pull 3-4 together with your mount.

HighmountainKill and skin Bristlefur Bears. I think this place is not that good as the others, but still a pretty decent place.