[MUDA-ZUKURI] creates a desktop machine that blows a plastic bag in the wind.
[@WillowCreative_] shows off a wolf head assembly
[Sarah Spencer] and [John Spencer] create an open source hardware automatic thread color changer for knitting machines.
The mask with a diffusor on can be seen in a later tweet.
Details are light but [natalie] creates animatronic robot singers.
[Indoorgeek] creates a mechanical 7 segment display using PCB coils a 3D printed housing and neodymium magnets.
Not much detail but @CHA2trico shows off a stunning cyber visor that looks like a face shield with an OLED screen behind it.
[Ekaggrat Singh Kalsi] creates GETULA, a 3D printed "chain clock" that morphs digits from a stepper motor fed chain.
Hackster.io has a nice writeup as well.
[Jason Huggins] creates automated phone tapping robots.
It looks like many if not all of the designs are open source hardware.
Tapster.io has a suite of robots for sale.
[Joris Wegner] creates an ouija board that moves without human interaction