I'm having trouble getting the Search bar under "This is a remix" to gimme the original models, so here are the direct links in the meantime:

Guitar Wall Hanger:
https://www.thingiverse.com/thing:1051357

Celtic Guitar Cavity Decoration:
https://www.thingiverse.com/thing:2558149/files

I was looking through which guitar bracket to print and happened across that Celtic knot, so I combinated the two. :D

UPDATE: I saw a remix of the original guitar holder that had had cavities for wooden dowels/pegs placed inside of it, so I re-incorporated that idea into my remix-----only, I made the pegs 3D-printable as well! Printing the pegs separately, and on their long flat side, will have the effect of adding a longways grain, similar to actual wood dowels. If the original bracket design has any particular structural weakness, it seems to me only to be that the grain of its layers runs perpendicular to gravity; so, if the layers adhere any less than absolutely, it may sheer and drop our guitars! Giving it internal longways grain, crossways to the exterior, should be more than enough for even a bass....in my personal opinion. I HAVE printed PLA drumsticks with a longways grain, and those seem practically indestructible even compared to real wood drumsticks, so I'll say that's an excellent test-comparison to judge by. Just be sure to be liberal with whatever super-glue or epoxy you intend to use; this design should only fail if the pegs actually pull out free from either the front half or the back half, supposing that the outside layers ever manage to split regardless.