Uncle amiibo

Uncle amiibo is a robot that appears in every kingdom except Darker Side. Upon talking to him, he will ask you if you wish to tap an amiibo. If you say yes, a screen will show up asking you to tap an amiibo. You can unlock certain outfits by doing this (without paying for them at a Crazy Cap store). He appears next to the Hint Toad in every kingdom.

You can also receive hints relating to the locations of Power Moons. After tapping an amiibo, you will have to wait for five minutes while that amiibo searches for Power Moons. After the five minutes are up, the location of a Power Moon will be marked on the map.

Uncle amiibo will not initially appear in Dark Side. He will appear, however, after the "Arrival at Rabbit Ridge!" Multi Moon is collected.

Locations

Uncle amiibo appears in every kingdom next to the Hint Toad, with the exception of Darker Side.

Mushroom Kingdom
Cap Kingdom
Cascade Kingdom
Sand Kingdom
Lake Kingdom
Wooded Kingdom
Cloud Kingdom
Lost Kingdom
Metro Kingdom
Snow Kingdom
Seaside Kingdom
Luncheon Kingdom
Ruined Kingdom
Bowser's Kingdom
Moon Kingdom
Dark Side