This Zelda sword and shield (of which there are two sets, one for Ocarina of Time and one for Twilight Princess) were made by Fiberglass Blades, a small custom accessory and weapon builder specialising in cosplay gear. If you think the shield looks enormous and heavy, well, you’re only half right.
It only looks heavy, thanks to a lavish helping of automotive paint that gives it that “steel” appearance. It’s actually made of resin, with a foam-filled interior to ensure that the shield is actually extremely light, should you want to actually use it for cosplay (and don’t have the guns to lug around a proper metal shield all day).
The swords are similar, made again of resin but this time reinforced with aluminium and fiberglass rods.
These aren’t museum pieces; you can actually buy them, with contact info at the link below.
[Fibreglass Blades, thanks Geoff!]