A brief description of the manga The Useless Tamer Will Turn into the Top Unconsciously by My Previous Life Knowledge:
As a result of an accident, the main character Varius died and was reborn.
He was shocked to find that, in this new world, his previous work as a Tamer in the previous world was deemed to be low-grade work in this new world.
Taking his knowledge from his previous life as a basis, he then applied unique buffs to his animals, restoring them to the absolute power that he once possessed.
With this power, he strove to start his life as an adventurer. But everything turned out to be not so simple …