- The war is over, and some believed dead have been treated, revived, and are recovering under strict Ministry surveillance. Harry is in isolation in St. Mungo's. The Prophet claims he's catatonic. The Order claims he's being held hostage by a Ministry conspiracy. The Ministry is busy consolidating its power base under a new Minister, but seems to be continuing some of the practices of the Voldemort Ministry. (Muggleborn Registry, required Hogwarts attendance, Dementors as crowd control, whatever.) Can Colin and/or Snape organize a break-out of the war casualties ward and find out what's really happening to Harry? Can they organize a coup to stop the Ministry before the Wizarding World becomes a police state? Viva la revolucion!
- When Voldemort "disappears" Narcissa and/or Draco to compel Lucius's cooperation, the Dark Lord fails to consider the deep bonds of family in pureblood tradition. What will Lucius do when faced with such loss? To whom will he turn for alliance/comfort/recovery? How much damage can Lucius do to Voldemort's cause should he choose to fight instead of flee? (Up to writer what "disappeared" can mean; could be First or Second War, take it as AU as you like.)
-the Muggleborn Railroad - Ted Tonks and Dean Thomas weren't just on the run - they were runners for the Muggleborn Railroad, helping victims of the Registration Commission or those in hiding get out of England, find their families, get new wands or identities, etc.
- After the war, Harry is hugely powerful but terribly scarred/maimed (author's choice). Rejected by society, brushed under the rug by the Ministry, he becomes a recluse and continually sabotages his own recovery. He resists the efforts of friends and adopted family to draw him out. Maybe what he needs is the effort of a former enemy? (ex-DE pairing preferred)