Eberron, you get a new class (Artificer), 4 new races (Kalashtar, Shifters/Half-Werewolves, Changelings and Warforged) plus playable versions of Goblins, Bugbears, Hobgoblins, Orcs.
personally would love if Oriental Adventures was added as a DLC so we can have playable Vanaras/Monkeyfolk but I doubt WOTC would allow it, I get that the name might be changed to something else.
