I created this model for myself, because I've many items that can be inserted into holes for them to be easier to find. I hope you'll like it.

This model is open source and was made in TinkerCAD. You can modify it at the following link:

https://www.tinkercad.com/things/75tUCBDH23a

Now available in three different sizes. We recommend printing the full size, 160x160, but if this would be a too long print for you, or too much material is required, try the 120x120 or 140x120 versions: the holes are the same size but the model is redesigned to be smaller.

Hint: if you want to print the large version (the one in the pictures) but the required time is too much, you can try a single wall and minimal infill, and reduce the number of bottom/top layers. I tried it and even in this way, the part will be resistant enough for real world usage, because of the way the object is shaped it remains solid and the time/material will be cut in half.

The object prints well in PLA. If you want to make it more sturdy, PETG is a good option, assuming you have good settings not causing too much stringing.