From Angle Rotation Animation to Arbitrary Rotation

Hi, I'm a student who is learning Unity now. We are going to implement our character spot turn. Currently, we have animations like left turn 45, 90, 135, 180 and right turn 45, 90, 135, 180. I put all the animations into blend tree. Now the question is how can we implement rotation on Arbitrary Rotation? Currently we only could turn specific angles.

If you could provide me some specific script or examples, that's great. You could also give me some keywords about the technology and I could learn by myself. Thanks!