Giant Killer
ME3: Defeat a harvester.
Tunnel Rat
ME3: Survive the swarm.
Untouchable
ME3: Escape a Reaper in the galaxy map.
World Shaker
ME3: Destroy an Atlas dropped from orbit.
Savior
ME3: Free Omega from Cerberus Occupation.
Liberator
ME3: Stop a Cerberus kidnapping.
Mobilizer
ME3: Bring a veteran officer aboard.
Lost and Found
ME3: Dispatch 10 probes to retrieve people or resources in Reaper territory.
Gunsmith
ME3: Upgrade any weapon to level 10.
Always Prepared
ME3: Obtain two non-customizable suits of armor.
Shopaholic
ME3: Visit a store in the single-player campaign.
Bringer of War
ME3: Chase down an assassin.
Mail Slot
ME3: Kill 10 guardians with headshots from the front while their shields are raised.
A Personal Touch
ME3: Modify a weapon.
Driven
ME3: Return to active duty.
No One Left Behind
ME2: Keep your team alive through the suicide mission
Merciless
ME2: Make 20 enemies scream as they fall or are set on fire
Weapon Specialist
ME2: Fully upgrade a weapon
Bruiser
Kill 100 enemies with melee attacks in Mass Effect 1, 2 or 3
Mission Accomplished
ME2: Save humanity throughout the galaxy from certain annihilation