The Penne Holder

Printed at 100% size, this pen holder will hold anything up to Sharpie-size.  The raked angle towards the back both allows holding longer implements and makes pens at the back easier to reach without fumbling through the others.

Also holds dried spaghetti.  Not fresh, though.  Or cooked.

Printing

Infill isn't critical.  I printed mine at 15%.

You don't need supports.

You want “Detect thin walls” switched off, otherwise it makes a bit of a mess around the upper edges.

There are a couple of minor overhangs on the underside, but they don't affect the print and the residue can be easily removed post-print.