This is Derrick Aquino[1]'s adaption of AJsRaceway[2]'s minifigure display [3].
Derrick's version [4] increases the size allowing for more minifigures and their large props to fit.
These hex frames require a 3x4 baseplate with 4 center studs, part 88646 [5].

[1] https://www.thingiverse.com/vampyrex13/designs
[2] https://www.thingiverse.com/ajsraceway/designs
[3] https://www.thingiverse.com/thing:3901517
[4] https://www.thingiverse.com/thing:5238208
[5] https://www.bricklink.com/v2/catalog/catalogitem.page?P=88646#T=C&C=11