Lifla- Head inside the cave by the giant tree, and you will encounter a deer trapped in a spell. Free it then go back and talk to it.
Beartooth Cave - Inside at the back of the cave. Requires some leg work following the tunnels.
Iquili's Den - Inside the cave is the fox Iquili. Takes a bit of walking and jumping to find him at the very top.
To add. If anyone needs help with first cave, to enter the cave for Lifla, you will need to solve a puzzle. Go to the glowing area right outside of the cave and activate it by pressing X to bring your light out then A to Use. Then you will need to fly through 3 gates in the area, they will glow white and you can see them from afar. Once you fly through all three, go back to same area outside cave and activate it by pressing X then A. You will see three lights on the area touching the center floating piece.