What are the best/most interesting locomotion systems? What are we lacking or overlooking? For the most part I have very impressed by locomotion in most games. I feel like most developer are very scared to innovate and explore new locomotion systems, so we are stick with very boring safe movement like sliding/teleporting.

For me, Lone Echo/Echo Arena is the undisputed king of VR locomotion. It's the most immersive/flow state inducing experience I've had in VR. 

Jet Island was also quite good. The problem with Jet Island is the locomotion system is very well designed but the gameplay itself feels very tacked on. 

What else is out there pushing the boundaries?