Here is the full list of all 50 I Am Setsuna trophies - there are 40 bronze, 7 silver, 2 gold and 1 platinum.
Used one megalixir.
Listened to all the youth's lines and defeated him.
Met the youth.
Met Eutess.
Used combos in Momentum mode 30 times.
Inflicted 500 damage in a single hit.
Ate Starberry Cake.
Ate Nive Vegetable Stew.
Ate Gatherington Fries.
Ate Gaia's Blessings Stew.
Saw ???.
Ate Horse Oak Casserole.
Met Rhydderch.
Met Sayagi.
Met Cornelius.
Saw the Apparth Ruins.
Met Hydor.
Made one monster drop eight materials at once.
Defeated ten enemies with Over Kill.
Defeated enemies with all Kill types.
Met Akash.
Used Momentum mode 100 times.
Used Momentum mode ten times in a single battle.
Met Freyja.
Defeated ten enemies with Exact Kill.
Made one monster drop four materials at once.
Met Raishin.
Met Hapsper.
Obtained all trophies.
Saw the Moolbeld Ruins.
Saw the Laniff Ruins.
Sailed on the exploratory ship.
Obtained the Genesis spritnite.
Obtained the Holy Light spritnite.
Obtained the Gearadia spritnite.
Obtained the Rebellion spritnite.
Obtained the Doom spritnite.
Obtained the Eclipse spritnite.
Obtained the Dragnarok spritnite.
Defeated all members of the Pengy species.
Defeated all members of the Hoot-Hoot species.
Defeated all the Spritnite-Eaten Monsters.
Defeated the Dark Samsara's final form.
Defeated the Ruler of Time.
Inflicted 1000 damage in a single hit.
Fluxation occurred ten times in Command Spritnite.
Fluxation occurred ten times in Support Spritnite.
Fluxation occurred four times in a single battle.
Fluxation occurred 200 times.
Added maximum Fluxes to a spritnite stone.