Here's an easy to print, modulable toothbrush holder. Can be combined to hold any number of toothbrushes. I included models for 1 and 2 and the F3D design so you can change it to fit your needs.
Attaches with 3 M3 screws.
I can export this in different combinations if needed, just post a request in the comments.
The author hasn't provided the model origin yet.