NAME TAG

No job villager, not an Armorer, not a Librarian, not any of the thirteen, lists a name tag in its trade table at any tier. The Wandering Trader with his two leashed llamas is the only source, and even he only carries one occasionally, out of his common stock rather than a guaranteed offer.

Name tag is a utility item rather than a material or a weapon, which is why it sits on the trader's stock next to potions and dyed ice instead of near any raw resource. A crafting grid makes one from 1 × iron or gold nugget and 1 × paper.

Put a name tag on the trader himself and a named mob stops despawning, turning a passing merchant you may never see again into a shop you can walk back to on purpose.

The Wandering Trader sells a name tag for 1 emerald each, out of his common stock, when that stock happens to include it. He does not buy one back off a player either, the offer only ever runs one way.

No standard village profession lists name tag in its trade table at any tier, so this one roaming merchant is the entire market for it, not the best of several sellers.

He asks 1 emerald each, and 33 of the other 75 come cheaper. Price is the easy part: he draws his stock from a shared pool, so catching one that happens to be carrying name tag is the real constraint.

The Wandering Trader asks 1 emerald for a name tag. 8 of the 72 villagers that pay emeralds, emptied out:

a lava bucket against 26 flint for the same 1 emerald, 26 times the carrying, and the shortest wait is the Leatherworker at 37.5 real seconds of shelf, gathering not counted.

The Wandering Trader is not part of any village. He arrives on his own near wherever a player is playing, with two leashed trader llamas behind him, stays for roughly forty minutes to an hour, and then vanishes whether or not a trade happened. There is no workstation to place and no job block to break, so the usual tricks for steering a regular villager toward a particular offer do nothing for him.

He does not buy a name tag off a player, only sells it, so the offer runs one direction: emeralds out of an inventory, up to 1 name tag into it per visit if the common-pool roll included it at all.

Each trader carries only a slice of his full stock list, so the one standing in front of a player may simply not have a name tag that day. If he does, and more than one visit's worth is wanted, put one on him: a named mob will not despawn, turning that passing merchant into a permanent shop instead.

What a full stack costs: he asks 1 emerald each, so a full stack of 64 comes to 64 emeralds.

Buy his whole stock the moment you find it. A Wandering Trader who has already sold his name tags for the visit will not roll another one before he despawns, so there is no reason to leave any on the shelf once he has been located.

Name one to fix the problem for good. Tagging the trader himself removes the guesswork entirely, since a permanent merchant beats hoping the next roaming one happens to carry the same offer.

Also on the wandering trader's list: packed ice, blue ice, gunpowder, podzol, potion of invisibility, and acacia log.

Naming a mob keeps the game from removing it when you walk away, which is the real reason the tag is worth emeralds. A named wandering trader stays put instead of leaving on his timer, and a named animal in a pen survives being loaded and unloaded a hundred times.

The tag has to be renamed on an anvil before it works, and that costs a level, so the true price of a tag is the trade plus the anvil. It does not work on a player and it does not work on the ender dragon, and once a name is on a mob only a second tag will change it.

A blank name tag does nothing. It has to be renamed on an anvil first, which costs a level, and only then will it work on a mob. That step catches out most people who find their first one in a dungeon chest.

A few names change behaviour rather than only labelling it. A sheep called jeb_ cycles through colours, and a rabbit called Toast wears a particular skin, both of which have been in the game for years.

It works on almost everything with a health bar, but not on a player and not on the ender dragon, and the tag is used up the moment it lands.