Thank you! I guess you have to be an EU baby to know half of those, I'll have to research them.
I'll give a brief outline, so that you still have some reading to do on your own.
Chiss: Originally introduced by Timothy Zahn in the Thrawn trilogy (Heir to the Empire; Dark Force Rising; The Last Command). Various Chiss then reappeared in Zahn's Hand of Thrawn duology (Specter of the Past, Vision of the Future), while a younger Thrawn appeared in Zahn's Outbound Flight. I believe there were a few appearances during the New Jedi Order series, then they played a major role in the Dark Nest trilogy. I'm actually disappointed the Chiss are in TOR, because Thrawn was originally introduced as one of the very few Chiss to have much contact with the galaxy beyond their own space (he was exiled for a pre-emptive military strike, illegal in Chiss society, and ended up joining Palpatine's Empire). The Chiss do, however, maintain a
very ordered society that complements both this Sith Empire and Palpatine's Empire, so they do seem like natural allies from that perspective. Up until now, the EU portrayed them as very insular and mysterious to the rest of the galaxy; perhaps, though, events in this timeframe explain for that in the time periods around and after the movies.
Miraluka: The only Miraluka I'm all that familiar with was a companion in Knights of the Old Republic II: The Sith Lords. Force-sensitive "near-human" (i.e., they look mostly human) species, none of whom who have physical eyes and therefore "see" through the Force.
Mirialan: Two Jedi during the Clone Wars - Luminara Undili and Barriss Offee - were of this species, but I don't think they've had much EU exposure beyond those two characters.
Rattataki: Never heard of it before TOR, so I'm pretty sure it's a new species for the game.
Sith Pureblood: Last remaining "pure" descendants of the original Sith species conquered millennia before TOR by Dark Jedi who had been exiled after losing a war with the Jedi Order. Those exiled Jedi styled themselves "Dark Lords of the Sith" after conquering Korriban, thus establishing the first Sith Order and the first Sith Empire.
Zabrak: Darth Maul is the best known example of a Zabrak. KOTOR2 included a Zabrak companion. This species is sometimes also called "Iridonian," due to being from a planet called Iridonia. Some Zabrak were also from Dathomir, and often were a subject species of dark side Force-users called Nightsisters.
Twi'lek are pretty ubiquitous in SW movies and EU alike, so you probably recognize that species.
