A while back I purchased a baseball bat for home defense (Welcome to Canada).  I had it leaning in a corner, and it felt kind of odd to just have it leaning there, so I busted out 3D Builder and set up a wall mountable baseball bat holder.  It now holds towels in my bathroom.

I don't have any screws that I could screw in with an allen wrench, so I put a hole in the model large enough to fit a standard screw driver through.  Turned out bettter than I expected, although I should really re-print them in black for better aesthetics.

I've had this up since December 2020 (about two years).  No issues with warping or anything at this point.

If I were to redo the model, I'd change the portion that touches the wall to be a little thicker so it's easier to drop a towel behind it.  Other than that it's pretty perfect.

Print the model on its side for best strength.

Supported screw size:
Screw head: 10mm
Screw width: 4mm

Bat dimensions:
Thickness: 3cm
Length: 63.5cm
Base: 4.5cm

Baseball bat I used:
“Baseball Bat Used for Baseball and self Defense,Alloy Steel,25 Inch (Black)” from Amazon: https://www.amazon.ca/gp/product/B082PK5HV5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1