ME3: Mission accomplished.

ME3: Defeat an old adversary.

ME3: Extract ancient technology.

ME3: Call down an orbital strike.

ME3: Deliver most of the Galaxy at War assets to the final conflict.

ME3: Stop an out-of-control scheme before it's too late.

Establish or rekindle a romantic relationship in all three games in Mass Effect Legendary Edition

ME3: Explore a lost city.

ME3: Defeat a harvester.

ME3: Kill a brute while it's charging you.

Kill 100 enemies with melee attacks in Mass Effect 1, 2 or 3

ME3: Stop a Cerberus kidnapping.

ME3: Bring a veteran officer aboard.