Thumbs up Gesture
The thumbs up gesture can be used to cheer other players, or simply as an extra level of expression.
To do a thumbs up, pull the trigger on your controller to make a fist, and then hold your hand in front of you horizontally, after a short period of time you will do a thumbs up gesture.
The point gesture can be used to select a player and open their profile or can be used to say "Hey, look at that!". The point gesture can also be used to open the Expresso menu.
To use the point gesture you have to press the B/Y button on Oculus, Menu button on Vive/Windows MR or the Triangle/Square button on PSVR.
Share Cam Gesture
The share cam gesture can be used to take a quick pic without having to bring out your camera. To use the share cam gesture, bring both of your hands in front of your face and hold them parallel to each other, once you see a camera icon pull the trigger and you will instantly take a picture.