Leviathan DLC introduces several new planets, systems and war assets to the basic version. You can find them listed below.
Dextrorotational War Assets
Triginta Petra (Lenal system in Sigurd's Cradle cluster) [10 points].
Zombie mind map
Chalkhos (Mil system in the Sigurd's Cradle cluster) [30 points].
Void Devils Fighter Wing
Heshtok (Kyzil system in the Shrike Abyssal cluster) [30 points].
Vorcha Labor Team
Tyrix asteroid in Thal system (Shrike Abyssal cluster) [15 points].
Illium (Tasale system in the Crescent Nebula cluster) [40 points].
Governor Grothan Pazness
Cholis (Indris system in the Kite's Nest cluster) [20 points]
Heat Deduction from Synthetic Diamonds
Bres (Balor system in Caleston Rift cluster) [25 points]