Here is the full list of all 21 Ys SEVEN achievements.
Complete the game on any difficulty.
Defeat all titanos.
Conquer the Moon Dragon, Ze-Kalion.
Conquer the Sea Dragon, O-Balon.
Die by drowning.
Conquer the Wind Dragon, Mu-Anti.
Conquer the Flame Dragon, Angue-Barl.
Die by walking over thorns.
Conquer the Earth Dragon, Rada-Manj.
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.
Unlock all bestiary entries for all non-boss, non-titano foes.
Find all the missing pikkards.
Learn every skill.
Raise all of any one character's skills to max level.
Buy every item from the Zanzibar Firm.
Synthesize each Spirit Elixir at least once.
Synthesize all Dragon Stone weapons.
Complete the game on Nightmare difficulty.
Obtain all other achievements.