Today Firaxis revealed the second last civilization and an associated leader: We are getting Russia and Catherine the Great.
Russia is a cultural and scientific civ with a starting bias for tundra and furs. Russia has as UUs Cossacks and the Katyusha, and gets as their associated wonder the Hermitage. For more information have a look at the thread here.
Catherine the Great is also cultural and scientific, with also a starting bias for tundra. She gets more culture from displayed great works, and she dislikes players who compete with her for great works. For more info check the Catherine thread here.