Retro Basement
The base used by my VrChat world Retro Basement. You can check out Retro Basement here:https://vrchat.com/home/launch?worldId=wrld_68014da2-6c91-4ae1-83e0-6574253c51fd
This base is textured and has a ceiling, but nothing else. This base is left blank so you can customize it any way you want to. Also included is the .blend file for the base, but, opening this in the latest Blender causes all the ram to get eaten up (I have 32GB)! So, proceed with caution.
The base is on the small side, as in Avatars sized 1.68 or greater will either touch the ceiling or clip through it. Furniture and avatars will also be cramped together as well, so I recommend you make it taller and wider. See my world above for an example of this. You can do this from within Unity Editor, or by using the .blend file (If you can get it to load without it using all your ram, lol).
A fbx and blend file.