I've seen some gold money that was paper money with enough gold leaf on it to be a store of value as well as medium of exchange. At least I assume it does... Its really cool looking. But I don't own any.
If you want whole coins to be gold, or electrum so its not super soft (that's gold and silver mixed), then I think we'll need to mine the Psyche asteroids. Supposedly there's enough gold in those asteroids to make gold worthless, if it were all brought back to earth.
What I like about the possibility of gold becoming transactional money again is, the existence of bitcoin might prevent debasement, since any debasement will cause a flight to safety into bitcoin. Or the gold money gets debased, but its fine because bitcoin exists - then democracies can be retardedly irresponsible and people don't have to fear the socialist collapse and the genocides they invite.

