A camcorder, a floppy disk, a CD-ROM, a film (for a camera), maybe even the fountain pen.
All of which I can recognise, but all of which will probably leave my daughters baffled if I were to ask them what it was...
I think we have precedent in the iconography of specialist occupations that have already existed in preindustrial times. The various brewing implements that adorn the labels of many breweries, the geometry implements that now only live on in freemasonry.. They all have names, but those names are lost to everybody but those who enjoy accumulating knowledge of old-timey things. Baffled, yes. But the world already is full of that kind of echoes from the past, it's not like someone is confused by them. Those who might consider a box of 3.5" a box of old save icons grew up with those save icons, it's the world they know.
It is interesting how iconography links to timeless design. Function and appearance have a way of coexisting in good design so the "idea" of something gets into semiotics.
Disk storage is a timeless concept. It's absent now but will no doubt return in some new guise on the next wave of materials science and storage tech.
The pen is timeless too.
Perhaps the weird one is the classic phone handset. My daughter who never saw one except maybe on a cartoon, instantly knew what to do with an old 1970s rotary I was hacking. The design "reaches out" and suggests its usage. Partly that's our monkey brains that sees tools and uses in everything.
How did your daughter immediately grasp those non-obvious, hidden concepts?
I'm convinced she saw it in a cartoon like Dora or Fireman Sam. But didn't hesitate to pick up the handset and put it to her ear.
EDIT:
Damnit I just had a flash of insight... thanks for the memory jolt.
As a baby she had a modern version of something like this [0] (hope the image loads for you). They still make them almost the same. It's a "walker/activity toy" with a rotary dial that made a sound and a phone handset.
[0] https://i.pinimg.com/originals/fd/28/21/fd28216d19251b2d7895...
That's such an interesting point. Having grown up with landlines (DTMF and initially pulse-dialing ones), I was trying to do the very opposite with my mobile phone just yesterday! The cellular connection was atrocious, with my calls being rejected or silenced regardless of the carrier. I attempted to start the call with an empty number so that I could hear that the dialing tones were correct myself - of course, it didn't let me. I don't suppose the dialing stage of a modern mobile phone is analogue anyway, is it?