Our user Rac made this great overview over all the civs, which we know so far, or very likely assume. We know the base game has 30 civs, plus Shawnee as DLC. We do not have a good idea yet about what civs will be in the 2 DLC packs, but obviously we are speculating, see this thread. Let us know if we did not see any evidence yet, and otherwise speculate with us!