Thanks to phillip9933 on Reddit for the original design. Here's a link to that one: https://www.prusaprinters.org/prints/69954-logitech-g502-lightspeed-pinky-rest

This is my remix of his pinky rest, extended for different grip types and with optional slots for 3/4 of replacement pack of mouse skates (found easily on Amazon) for the Logitech G502 Lightspeed Hero. Should fit the regular Hero too I think, but will likely leave a large opening at the bottom due to the shape difference. Once you get the perfect print, you will have to glue a nut or magnet or something in the obvious cylinder so the magnetic closure has something to hold on to. The print shown above in the images is my very first test print after not printing anything for months, so it looks kinda janky, presumably due to moisture in the filament. Ignore any jank, as that's from the printer/filament and not the design.

Printing:

If printing the "flat bottom" one, print bottom down to ensure maximum smoothness and surface area for the skates to stick to. Preferably on glass.

If printing the one with the skate slots, I'd recommend printing with fairly dense support. Doesn't need to be as smooth since the skates have a physical barrier preventing them from sliding around over time, but you could clear-coat anyway it if you want.

SOMEONE PLEASE REMIX THIS and make it perfect. .Step file included. It's pretty good, but I'm not good enough with CAD to get it to perfection. The thumb rest area needs to be enlarged and shaped to be more like the original, and parts that touch the grooves on the bottom and back of the mouse could be enlarged to fit the actual shape of the grooves instead of just being flat and filleted. All the edge faces could be redone to make them one sweeping edge instead of being multiple in some locations, and the original "triangles" texture/design could be added as debossment for a more OEM appearance. The pinky rest design could be made smaller to appear more symmetrical with the opposite side of the mouse when silhouetted from above as well. Hell, I'd pay someone for this design to be perfected, honestly.

Creality

Doesn't Matter

What does this even actuallly mean? Make it as fine as you can. 0.4 nozzle here