Yes four in this order.
Falleen, fascinating species and very poorly covered in EU. Not a lot of appearances. Liked Xizor and the few Falleen that make appearances.
Chiss, again fascinating culture and appearance. Decently covered in EU thanks to Zahn, Alston and Stackpole. Gave us Thrawn and Sev'rance Tann.
Yevetha, great species as villains, the most die hard fighters, done great injustice by their side stories and general lack of coverage. they were one of the only instances of an Empire oppressed people being MORE Evil than their oppressors.
Yuuzhan Vong. Loved the social structure, the well documented ships, weapons and characters. They are certainly the most fleshed out species of all in SWs and they were the most diverse too whereas most species fell into stereotypes like Twilek=dancer or criminal or jedi, Sullustan=pilot, Hutt= crime lord, Nikto, Weequey, Rodian= bounty hunter or mercenary. They had a whole working culture that seemed believable and such great characters like Nom Anor, Czulkang Lah, Harrar, and Nas Choka.