I've joined the Discord,but I am in china and have no VPN so I cannot join the discussion or share my robot designs:(
Also...is there any pneumatic 4-Bar flipper before I post this comment?
There aren't. For now we just have simple rotation and linear actuation. People have been able to combine the two to create something that moves in a way similar to a 4-bar linkage. It isn't exactly the same, but it is close.