The community in Hiveworkshop has done a very great job in making skins and models for Reforged. Although some needs improvement (but I’m sure you can fix and tweak them), here’s what I recommend for such certain characters and entities that simply reused generic models:
Orgrimmar Armory:
https://www.hiveworkshop.com/threads/orc-blacksmith-reforged.322923/
Khanzo:
https://www.hiveworkshop.com/threads/reforged-beastmaster-orc-skin.321857/
Haomarush:
https://www.hiveworkshop.com/threads/green-chaos-blademaster.323020/
Genjuros:
https://www.hiveworkshop.com/threads/orc-champion.324384/
Draenei Elite Assassin: (needs improvement but you can tweak it)
https://www.hiveworkshop.com/threads/dranai-female-reforged.322864/
Orc Spearthrowers: (in replacement of Forest Trolls)
https://www.hiveworkshop.com/threads/orc-spearthrowers-pack-reforged.323159/
Mazrigos and Thok’feroth:
https://www.hiveworkshop.com/threads/reforged-second-war-orc-deathknight.323112/
Militia Commander: (Knight)
https://www.hiveworkshop.com/threads/reforged-second-war-human-knight-paladin.323098/
Royal Guard: (Paladin)
https://www.hiveworkshop.com/threads/reforged-second-war-human-knight-paladin.323098/
Kul Tiran Marine: (needs tweak for Kul Tiran textures)
https://www.hiveworkshop.com/threads/heavy-musketeer.322978/
High Elf Archer:
https://www.hiveworkshop.com/threads/silver-covenant-archer-request.323094/
Low tier Ogre Mound:
https://www.hiveworkshop.com/threads/reforged-neutral-beast-lair-and-derivatives.323209/
High tier Ogre Mound:
https://www.hiveworkshop.com/threads/ogre-mound-and-derivatives-reforged.323477/
Orgrimmar Barricade:
https://www.hiveworkshop.com/threads/spiked-barricade-reforged.322883/
Dark/Forsaken Archer:
https://www.hiveworkshop.com/threads/dark-ranger-reforged.323550/
Mathogg: (replace the weapon with a blander hammer/axe)
https://www.hiveworkshop.com/threads/ogrim-doomhammer-young-reforged.322863/
Garithos’ Elite Guard:
https://www.hiveworkshop.com/threads/republic-captain.324676/
Navy Swordsman:
https://www.hiveworkshop.com/threads/legionary.323039/
Crusader:
https://www.hiveworkshop.com/threads/centurion.324469/
Silvermoon Royal Guard:
https://www.hiveworkshop.com/threads/high-elf-spellbreaker-silver-covenant.324587/
Blood Elf Civilian/Prisoner/Refugee:
https://www.hiveworkshop.com/threads/female-blood-elf-villager-reforged-request.324703/
Ner’zhul:
https://www.hiveworkshop.com/threads/nerzhul-reforged-green-and-maghar-skin.324451/
It’s still not yet complete for the likes of Anetheron, Mephistroth, Calfax, Bael’gun, Sen’jin, Zar’jira, and etc. but I will update this list when more community made resources come.
But of course, give credits to these model/skin artists!