Do you store bread in the freezer?  Do you microwave it to defrost it? If you put 2 slices in the microwave, the top one will defrost first.  If you try to stand them up, they will always fall over as they thaw.   You don't want to put metal items in the microwave right??   This simple little print job will hold them upright (ish) while they defrost and you will have  2 or 3 slices ready for your sandwiches in no time.  It worked fine for me 👍. PLA is a relatively 'safe' material for foodstuffs.   You may want to wash it first... OK, so this isn't a precision bit of equipment but be fair, how precise is your bread??