Full list of all 56 Tales of Zestiria achievements. It takes around 100-120 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there is 1 DLC pack containing 6 achievements.
This is proof that you've achieved the Stack 16 bonus skill, the highest echelon of Stack bonuses. Whether this is the end or just the beginning is up to you.