They are all the alt codes you can perform on Habbo.
How to do it
Computer
Make sure num lock is on, then hold down alt and enter the correct number sequence according to the correct symbol you want!
Laptop
Again, make sure num lock is on, then you must hold down fn and alt together, and use the blue numbers that overlap some keys and enter the code!
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(\__/)
(='.'=)
(")_(")