I bet this isn't the answer the questioner has in mind, but it seems to me to work tolerably well.
Anything that provides a substantial benefit to the holder but is only any use if you have money. For instance: a half-price voucher for some fantastically expensive musical production; a ticket entitling the bearer to attend the opening of a new shop selling (only) very fancy jewelry.
if a poor person came into possession of one of these things they could sell it to a rich person. But if I imagine (say) that I am desperately poor, I pull a newspaper out of a roadside litter bin to stuff inside my clothes to keep me warm at night, and out falls a voucher offering 20% off a new Ferrari, I'm probably not going to go out in search of a rich gearhead to sell it to.
A possibly more cogent objection is that
most things in this category will be of interest to some rich men but not all. (I don't think there is any level of wealth at which I would be very interested in a 20%-off voucher for Ferraris. Though I might try to sell one if I had it.)