As the name suggests, 7 Wonders: Wonder Pack includes new wonders for use with the 7 Wonders base game, with the wonders in question being:

The Great Wall of China, with the owner being able to build the stages of this wonder in any order (since the wall is, of course, a long horizontal wonder and not a primarily vertical one)

Stonehenge, with the amount of stone you have being important during its construction

Abu Simbel, in which leaders can be buried and mummified for bonus points

Manneken Pis, which is a revised version of the 7 Wonders: Manneken Pis wonder first released as a promotional item at Spiel 2010.