One artefact I got is quite ridiculous. And it had unusual story. A bismuthinite percussion set (large stationary percussion instrument) which was brought to me by a weremammoth (weremammoths were swarming my fortress in its early years, and each one was bringing an artefact). The beast showed up, killed a sentry cat with said instrument, then a monitor lizard, then entered the ocean, only to transform back in the middle. It dropped the instrument, made a few steps, and drowned. Later similar feat (i.e. drowning) was repeated by a couple of other weremammoths.
It took me several years to make a battery of "ocean suckers", pumps which created a current, which brought the instrument to the shore. Even before my dwarves got their paws on it, they were referencing it in their own artefacts. The name of it is "The Root of Growth". And it isn't the only stationary percussion set, my dwarves made a garnierite one (but decorated with adamantine), named "The Solitary General". Now I need a couple of guitars and can make a metal band.
Other funny artefact is an iron toy hammer - I mean, if it is made with iron, can be this still counted as a toy?
Yet another is a cat bone buckler. Would you protect your life with cat-bone-anything? Because I wouldn't.
Of useless clothing I got a ramie headscarf, and a woollen right mitten.
One of my favourites was brought by an ettin or cyclops - it is a dwarf bone table. Good for negotiations with my outpost liaison.
But the most impossible is the nautilus shell chain. I can't even imagine how it looks like.