I think lasers are pretty wack when you think about them through this lens. A small, wand-like object in your hand can make light appear from seemingly nowhere. If it’s powerful enough it can set things on fire or blind people. Not to mention larger ones like laser cutters or the LLD, used to destroy missiles midflight. Thats sure to blow some feudal peasant minds
I can’t believe 3D Printing hasn’t been mentioned. Summoning figures from the ether would almost certainly get you tried as a witch.
I think 3D printers will really become mainstream when they’re a bit more capable.