A second package of extra stuff for the War For Cybertron game is being released next week (7th in the US, 8th in Europe - I think we count as US?).
Extra characters and Maps are mentioned, but no other details yet.

Source is on the game itself, as the scrolling message on the menu pages.
(I hadn't played with it for about a week, so was wondering why this hadn't been mentioned on the global sites yet - the news seems to be that new... and no details yet as to which characters will be released this time)