I made a Batman coaster a while ago and I'm surprised I never made a matching keychain for it. So here are 3 versions, all based on the Michael Keaton version. 

V1 is the round batsignal type
V2 is the Bat symbol
V3 is the variant Bat symbol with added points on the tail

Print whichever version you like! Just change filament color above 2mm. 

Link to my Batman coaster:
https://www.printables.com/model/150220-batman-coaster