Here is the full list of all 21 Ys SEVEN achievements.
Unlock all bestiary entries for all non-boss, non-titano foes.
Die by walking over thorns.
Learn every skill.
Raise all of any one character's skills to max level.
Buy every item from the Zanzibar Firm.
Synthesize all Dragon Stone weapons.
Complete the game on Nightmare difficulty.
Obtain all other achievements.
Complete the game on any difficulty.
Synthesize each Spirit Elixir at least once.
Conquer the Moon Dragon, Ze-Kalion.
Conquer the Sea Dragon, O-Balon.
Die by drowning.
Defeat all titanos.
Conquer the Flame Dragon, Angue-Barl.
Conquer the Earth Dragon, Rada-Manj.
Conquer the Wind Dragon, Mu-Anti.
Find all the missing pikkards.
Survive against a beast intended specifically to kill you.
Defeat Geis in one-on-one combat.
Escort Tia back to Altago City completely unscathed, and without using any healing items.