Look for the Yggdrasilu nectar. 10 tips for starters in God of War: Ragnarok!

Yggdrasilu drops are secreted by protruding roots. They are hard to miss.

Another important, returning element in the game is the nectar of the World Tree. At some points of the game, you gain access to a boat and can explore freely. In these moments, look for bright droplets hanging from protruding roots. Get near them and wait for your companion to collect them.

They can be used to develop attributes. A sip of a given nectar can permanently reduce the cooldown of special abilities or increase vitality, luck, or strength. They drops are consumables. When you drink a sip of the nectar, your attributes will increase automatically.

Information on which attributes have been increased can be found in the codex and in the resources tab. Look for the "unique resources" category. Of course, you can only drink a single drop collected from a single spot, just like in the previous game.