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