Drow race, but only if they are given their own unique racial enhancement tree (Scorpion Wraith). Currently, no one *needs* to pay for drow, since they can be obtained through favor by playing F2P quests.
An LFM page on the charactar select screen.
Dragonmark-themed expansion pack, if it contains a raid and some racial enhancement trees for dragonmarked characters.
Edit: I welcome other people listing their own suggestions!