Here is the full list of all 44 Trials of Mana achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
First ride on Vuscav.
Open 100 treasure boxes.
First class switch.
Complete Chapter 1.
First cannon ride.
Purchase nitromyte for the listed price.
First encounter with Li'l Cactus.
First time learning a companion's chain ability.
First time learning a chain ability from an unexpected acquaintance.
First time learning an ability.
First time planting a seed.
Obtain all achievements.
Stop the end of the world.
Play with all six main characters.
Complete Duran's story.
Complete Angela's story.
Complete Kevin's story.
Complete Charlotte's story.
Complete Hawkeye's story.
Complete Riesz's story.
Complete Chapter 2.
Complete Chapter 3.
Complete Chapter 4.
Complete Chapter 5.
Complete Chapter 6.
First ride on Flammie.
Open 200 treasure boxes.
Accumulate at least 100,000 lucre.
Accumulate at least 500,000 lucre.
Learn 20 abilities as any character.
Learn all abilities as any character.
Defeat Anise on hard.
Defeat Mondoragon.
Defeat Dark Lich.
Defeat Archdemon.
Defeat Black Rabite.
Become a master swordsman.
Become a master magician.
Become a master fighter.
Become a master cleric.
Become a master thief.
Become a master guard.
Find Li'l Cactus in all possible areas.
Max out magic pot level.