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