Here is the list of playable alien races and the book they can be found in. This will be updated as new releases come out. A simple google search will give info on any of the races you may be unfamiliar with.
Age of Rebellion
Core: Bothan, Droid, Duros, Gran, human, Ithorian, Mon Calamari, Sullustian,
Strongholds of Resistence: Polis Massen, Quarren, Verpine
Stay on Target: Chadra-Fan, Dressellian, Xexto
Desperate Allies: Caamasi, Neimoidian, Gossam
Force and Destiny
Core: Cerean, Human, Kal Dor, Mirialan, Nautoian, Togruta, Twi'lek, Zabrak
Edge of the Empire
Core: Bothan, Droid, Gand, Human, Rodian, Trandoshan, Twi'lek, Wookie
Enter the Unknown: Chiss, Duros, Toydarian,
Fly Casual: Falleen, Gotal, Quarren
Dangerous Covenants: Aqualish, Klatooinian, Weequay
Far Horizons: Arcona, Gran, Chevin
Suns of Fortune: Corellian Human
Never trust the dice
