TheWoWDBTatto seems to be in two places - probably depends on what quests you have done on your toon. But you can check two places - to the left of Patchu or next to the left of the flight master.
Humanoid
Tatto
Stable Master
The highest voted Wowhead comments for this page. They are community notes, not TheWoWDB comments.
Tatto is located at (13.2, 48.8)
Details
This roster comes from the current game client's data files, so it is not a complete list of every NPC in the game - older world NPCs that are no longer in the modern client are absent.
Community notes from Wowhead · 4 comments
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Found him by the flight master.
Level and Map Tracking
The game data tunes Tatto for levels 30 to 70, Dragonflight content.