The lowly light-bulb. A real "edison" filimented light-bulb.
They don't make these (much) anymore, but you don't think too much about the fact. But they are relics now, but we wont think of them that way for another couple of decades. They are much like vacuum tubes (and in fact are the simplest form of vacuum tube - just a filament).
So if you have a few of these still, you might want to save them for your great grand children - you know, the ones who will be "Jacked into the Net" as an example of a relic.