It looks like the Leader cards & several other cards have been spoiled from the 2-Player Starter Set for Shadows of the Galaxy!
Shadows of the Galaxy 2-Player Starter Leaders:
This set will have 262 cards (around the same size as Spark of Rebellion). It looks like there's going to be 3 new mechanics in this set, 2 of which have been spoiled so far!
Bounty
Bounty is an ability that gives the opponent a reward for defeating or capturing the card. Cards & upgrades can grant the ability to cards, or some units can already have the Bounty ability printed on the card!
Capture
Capture is a way to temporarily remove a unit from the board - when you "capture" a unit, you place it face-down under the card that captured it.
Smuggle
No information has been officially released about this mechanic yet.