This list ("NPCs.txt") can be used to ignore all NPCs in the game.
It currently includes all 1149 NPCs (2024-04-19).
Close your Tibia client and then navigate to your Tibia installation directory.
On Windows, you will find the directory at %localappdata%\Tibia\packages\Tibia.
Then navigate to the conf\clientoptions.json file and open it using a text editor such as Notepad.
Scroll down to the bottom of the file where you will see blacklistedNames: [].
Simply copy all NPC names from this page ("NPCs.txt") and paste them inside the brackets [].
Save the file and start the Tibia client.
If you check your ignore list (Ctrl+I) you will now see all NPCs added there.
This does not include NPCs in houses (hirelings) as they have custom names.