I Think I've Figured Out All The Allied Races - World of Warcraft Forums
TL;DR: Final list is on the bottom. Everything else is reasoning to that list. First, let me list all of the (more-or-less confirmed) Allied Races. Alliance: Void Elf, Lightforged Draenei, Dark Iron Dwarf, Kul Tiran Human. Horde: Nightborne, Highmountain Tauren, Mag'har Orc, Zandalari Troll, Vulpera. Now let us list who all is in each Embassy, setting aside Anduin and Sylvanas. Alliance: Alleria Windrunner, High Exarch Turalyon, Moira Thaurissan, Genn Greymane, Gelbin Mekkatorque, Tyrande Whisperwind, Aysa Cloudsinger, and Prophet Velen (8 Total). Horde: Lady Liadrin, Baine Bloodhoof, Eitrigg, Rokhan, Trade Prince Gallywix, Nathanos Blightcaller, and Ji Firepaw (7). Now, let us list who give us what (more-or-less) confirmed Allied Race. Alliance: Alleria (Void Elf), Turalyon (Lightforged Draenei), Moira (Dark Iron Dwarves). Since Genn is the only candidate on the list who would reasonably give us Kul Tiran Humans, I will also add, Genn (Kul Tiran Humans). Horde: Liadrin (Nightborne), Baine (Highmountain Tauren), Eitrigg (Mag'har Orc). Since Rokhan is the only troll there and plays an important role in Zandalar, he likely gives us Zandalari Trolls. Since goblins share a model with the Vulpera, it is likely that Gallywix gives us Vulpera. Thus, I will also add, Rokhan (Zandalari Troll), Gallywix (Vulpera). This now leaves 4 people in the Alliance Embassy (Mekkatorque, Tyrande, Aysa, and Velen) along with 2 people in the Horde Embassy (Nathanos and Ji). Now, on the Allied Race screen there is only enough space for 6 Allied Races, and above I listed 4 Alliance Allied Races and 5 Horde Allied Races. This mean that, among the people left in the Alliance Embassy, 2 more will give us Allied Races, while in the Horde Embassy only 1 more will. Now it is important to note that there is a pattern to Allied Races (with one key exception): Each Allied Race thus far corresponds to and shared a (similar) model with just one Faction-Specific Race, and each Faction-Specific Race only gets one Allied Race. Thus, Highmountain Tauren correspond to Tauren and we shouldn't expect any more Tauren Allied Races. Lightforged Draenei correspond to Draenei and we shouldn't expect any more Draenei Allied Races. Dark Iron Dwarves correspond to Dwarves. Mag'har Orcs correspond to Orcs. Vulpera correspond to Goblins. Since we shouldn't expect any more Draenei Allied Races, and since Velen is chilling behind the counter unlike any of the other people who give us Allied Races, we should rule out Velen as someone who gives us an Allied Race. Thus, 2 Alliance Allied Races must be gotten from Tyrande, Mekkatorque, and Aysa. Now it seems easy to subtract a potential Allied-Race-Giver from both Horde and Alliance: The Pandaren. This is because, if we follow the pattern above, we should expect the Alliance to get 2 Allied Races corresponding to either Gnomes, Worgen, or Pandaren, while the Horde should get 1 Allied Race corresponding either to Undead or Pandaren. Since it seems unlikely that Blizzard will not give us an Undead Allied Race given the importance of the Undead (and Death in general) in this expansion, we should conclude that the missing Horde Allied Race will correspond to Undead, and that there will be no Horde Pandaren Allied Race. In turn, we should conclude that there will be no Alliance Pandaren Allied Race. We should thus also expect that neither Aysa nor Ji will give us Allied Races. Thus, the 2 Alliance Allied Races will come from Mekkatorque and Tyrande, while the 1 Horde Allied Race will come from Nathanos. Now we can see that Mekkatorque will give us the Allied Race which corresponds to Gnome (specifically, this Allied Race seems like it will be Cyborg Gnomes, probably called Junker Gnomes), so we must conclude that Tyrande will give us an Allied Race corresponding to Worgen. Meanwhile, Nathanos will give us an Allied Race corresponding to Undead. But wait, you object. (Now we get back to the "key exception" mentioned earlier.) What about the Allied Races corresponding to Night Elves and Blood Elves? Since Lady Liadrin is the only one in the Horde Embassy likely to give us an Allied Race corresponding to Blood Elves, and she gave us Nightborne, we should conclude that the Nightborne are the Allied Race which correspond to Blood Elves. On the Alliance side, we have the Void Elves. Given the above considerations, Void Elves must either correspond to Worgen or Night Elves. It should be obvious that the Void Elves correspond more to Night Elves than Worgen, given that they are elves. This becomes even clearer when we note that the Allied Race corresponding to Blood Elves (Nightborne) got the Night Elf model while the Allied Race corresponding to Night Elves (Void Elves) got the Blood Elf model. But why would Blizzard swap the models on us like that, when they haven't done so for any other Allied Race? The answer is obvious once one realizes that Tyrande will give us the Allied Race corresponding to Worgen. Tyrande will give us a Worgen-like Allied Race which uses the Night Elf model: In other words, Tyrande will give us the Original Worgen who were Night Elves that had first assumed the Pack Form. Now the pattern becomes clear: the Allied Race corresponding to Night Elves has the Blood Elf model because the Allied Race corresponding to Worgen will have the Night Elf model and (here's the real kicker) the Allied Race corresponding to Blood Elves has the Night Elf model because the Allied Race corresponding to Undead will have the Blood Elf model. They will be Darkfallen, or Blood Elf Undead. So we now get our final lists of Allied Races, which Race they correspond to, and who gives us them. Alliance: Alleria (Night Elves: Void Elf), Turalyon (Draenei: Lightforged Draenei), Moira (Dwarves: Dark Iron Dwarves), Genn (Humans: Kul Tiran Human), Mekkatorque (Gnomes: Junker Gnomes), and Tyrande (Worgen: Night Elf Worgen). Horde: Liadrin (Blood Elves: Nightborne), Baine (Tauren: Highmountain Tauren), Eitrigg (Orcs: Mag'har Orc), Rokhan (Trolls: Zandalari Trolls), Gallywix (Goblins: Vulpera), and Nathanos (Undead: Blood Elf Undead). So, if you were interested to know what to expect for the last few Allied Races, I feel I have a compelling case which shows us that they will be Junker Gnomes (see WoWhead and search google for more info, there isn't that much yet though), Night Elf Worgen, and Blood Elf Undead.
https://us.battle.net/forums/en/wow/topic/20769707765