Shelf Support Pegs (4 & 5mm pins)

thingiverse

Quick printing replacement part, even in PLA they can take a good bit of weight. These would be a bit stronger printed in 0.3 instead of 0.2 and with more infill, but if weight is that critical, your probably better off ordering metal parts. The original version was a 5mm pin, but if that is too tight, you can either run a die over the pin to shave it down or switch to the 4mm pin file. These were designed to print without supports.