The internet. Near instantaneous communication with anyone on earth who has access to it.

Magnets

Photography. Simple as that, would blow people's minds.

A remote control or any bluetooth-enabled devices. It's like spooky action at a distance. Just press a button on a little thing and it can make something else across the room do something on its own.

Fibre Optic cables still blow me away

I'd really love to sit a middle aged peasant down and watch them play GTA V

Quikclot. "Wait it's just clay powder?"

It doesn't need to be super advanced to be incredible.

I usually have a live cam playing on my 2nd screen. Right now I'm watching a bird feeder in Panama, full of tropical birds. Or I can watch another stream that's in NY State where there are Bluejays and Woodpeckers. Sometimes I have a tropical beach, or look at the jellyfishes in the Monterrey Bay Aquarium. I think that's magic.

Most of our weaponry.

Communications is huge.

Depending on how far back you go, almost anything. Tech has come a long way and it still seems to have endless possibilities. We just might be in a golden era. We once deemed things impossible and brushed them aside, now we are more accepting of them only being impossible for current tech. Interstellar travel for example is tech that's still far beyond us but we know we can get there.

I mean we gather these black rocks called silicone and refine them, then we cut them to plates and inscribe them with microscopic runes light and very secret mixtures. Next we use lighting on it to make it think for is.

All the sufficiently advanced ones, really.

I think it would be vaguely adorable if after I used the external water dispenser on my fridge a medieval age person hesitantly asked me if I descended from Moses.

• microwave ovens
• speakers (especially battery-powered Bluetooth, since they aren’t connected to anything)
• LEDs (light without noticeable heat)