I'm sure China would put in a bid for one, your life wouldn't be worth living after though you would need serious plastic surgery a new identity and even if you moved to China I'm pretty sure you would have a accident eventually.
As a normal person with no underground connections, maybe a significantly sized diamond? I don’t even know where to begin to be able to sell it. And any stolen large diamond will definitely raise alarms if I bring it anywhere legal to sell.
Or just any ol pawn shop on the bad side of town. Those guys never notify the police, even when they're legally obligated to do so. Although, if you go to the wrong pawn shop and they know it's stolen, they might just jack you themselves.
A famous work of art like the Mona Lisa, maybe? It would be super hard to steal and you might not be able to fence it because it's too hot. Something like that would immediately go viral on the news and everyone on the planet would be looking out for it.
That's not necessarily valuable, exactly. Yes, companies charge a lot for consumer ink jet printer ink, but prices go down dramatically when you're talking about commercial printing. A two liter bottle of high-end dye sublimation ink runs about $200 (might be up since I last bought in 2021), and the dye sublimation ink for the HP printer I operate costs about $700/10L.
If your printer has replaceable print heads that aren't part of the ink cartridge, and if you can retrofit a bulk ink system, then you quickly find out that ink is pretty inexpensive.