The first one I ever did was the enclosure bolts. Why tapered and requiring of a driver when hand tight is more than fine? So I grabbed 20 M3 6mm stainless socket cap bolts from [ here ], cheap enough for volume savings and plentiful enough for spares, while preventing rust with stainless. Matches the aluminum frame too.
Recently I added to the list with 4x M4 bolts and 4x M4 wingnuts for quick and dirty front enclosure panel "handles". Just be sure to grab regular steel bolts or this will be a pointless swap -- magnets don't work on stainless!