Here is the full list of all 21 Ys SEVEN achievements.
Learn every skill.
Obtain all other achievements.
Synthesize all Dragon Stone weapons.
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.
Complete the game on any difficulty.
Complete the game on Nightmare difficulty.
Unlock all bestiary entries for all non-boss, non-titano foes.
Conquer the Moon Dragon, Ze-Kalion.
Conquer the Sea Dragon, O-Balon.
Defeat all titanos.
Conquer the Wind Dragon, Mu-Anti.
Conquer the Flame Dragon, Angue-Barl.
Conquer the Earth Dragon, Rada-Manj.
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.
Die by walking over thorns.
Die by drowning.