This is a pretty specific design for my needs, but this allows a Clean Hydration ceramic lined insulated mug to fit nicely in a Tesla Model 3 cup holder, with a cup holder insert in it.
The included FreeCAD file would be VERY easy to adapt to your cup/mug and cup holder. Just adjust the sketch for the base and top, and it will update accordingly.
I have printed this in PLA+ and PETG, both worked fine.
This is the mug I use:
https://www.amazon.com/gp/product/B094DZV5FF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
The author marked this model as their own original creation.