More allied races

Since subraces, or "allied races", are now official but far from exhausted as an option, here are a few more suggestions. 

Humans

• Forsaken Humans: Functionally identical to Undead (ALIGNED WITH HORDE, having access to the same classes, having the same racial perks, start in the UD starting zone), but with a human-like appearance. They use skin textures specific to Death Knights and those of the Undead race (modified for a Human body mesh), and have glowing red eyes. Think of Nathanos Blightcaller as their template.

A Forsaken Human and a Forsaken Elf.

Blood Elves

• Forsaken Elves: Functionally identical to Undead (having access to the same classes, having the same racial perks, start in the UD starting zone), but with an elf-like appearance. They use skin textures specific to Death Knights and those of the Undead (modified for a Human body mesh), and have glowing red eyes. Think of Sylvanas or the Dark Rangers as their template
•  High Elves: Blue eyes instead of green ones, different appearance (no Saiyajin-haircuts!), different racial perks, ALIGNED WITH ALLIANCE.

Dwarves

• Wildhammer Dwarves: Standard Dwarves with Tattoos.

Orcs

•  Purebloods: Standard Draenor Orcs with brown skin.

A Mag’har Orc Pureblood

Trolls

• Forest Trolls: technically not really a sub-race since it would use an entirely different model, different animations and voice files. On the flip side, it’s already in the game.

Tauren

• Taunka: Tauren with Bison-like head meshes and different fur colors.
• Yaungol: Tauren with different horns and furs.

Undead:

•  Forsaken Skeletons: Functionally identical to Undead (having access to the same classes, having the same racial perks except cannibalize (get soulsucking instead), start in the UD starting zone), but with a skeletal appearanc.