Here is the full list of all 48 Persona 3 Reload achievements.
Performed 50 All-Out Attacks.
Obtained 10 Personas during Shuffle Time.
Initiated 50 Chance Encounters.
Ordered from a secret menu at the Iwatodai strip mall at night.
Defeated the Priestess.
Opened 50 treasure chests.
Defeated a rare, golden enemy.
Performed a Shift.
Performed a Dyad Fusion.
Joined the Specialized Extracurricular Execution Squad.
Obtained Orpheus.
Defeated the Empress and Emperor.
Defeated the Hierophant and the Lovers.
Defeated the Chariot and Justice.
Defeated the Hermit.
Defeated Fortune and Strength.
Defeated the Hanged Man.
Sealed Nyx.
Watched the good ending.
Obtained 10 Major Arcana during Shuffle Time.
Invited Elizabeth to your room.
Aced an exam.
Maxed out all Social Links.
Unlocked all Social Links.
Nurtured a romance.
Maxed out one Social Link.
Awakened all teammates' ultimate Personas.
Used all teammates' Theurgy.
Rescued a missing person.
Dealt over 999 damage in a single attack (All-Out Attacks excluded).
Discovered and conquered 10 Monad doors.
Used a total of 50 Twilight Fragments.
Encountered a Dark Zone in Tartarus.
Defeated the Reaper.
Performed a fusion with three or more Personas.
Obtained an item from a Persona Conception.
Fused Messiah.
Triggered a skill change during fusion.
Harvested a crop that you grew with a teammate.
Earned over a total of 50,000 yen from part-time jobs.
Maxed out one Social Stat.
Maxed out all Social Stats.
Spent an evening in the dorm with a teammate.
Nursed a cat back to full health.
Accepted an invitation to hang out five times.
Unlocked access to the remaining Major Arcana.
Unlocked a teammate's Combat Characteristic.
Acquired every Twilight Fragment in town.