Thrawn's Revenge is a large-scale mod for Empire at War: Forces of Corruption. It includes the events of the Galactic Civil War after Palpatine's death at Endor, up until the signing of the Pellaeon-Gavrisom treaty. If you own the Steam version of EaW, you will have to complete extra steps to run the mod after installation. Please see the manual for these steps.
Screenshots from the 1.2 release announcement. Nebula by Casperium.