1. Challenge Mode: Gold.
2. Heroic raid gear and achievements.
3. TCG mounts.
4. Profession kits.
5. PVP season carries (I'm a little fuzzy on the details, not sure it included a mount)
And just about anything else you can think of.
So if you've got the gold or dollars, someone will sell you damned near anything anybody else can get, except for world or server firsts.