In Neko Atsume, mementos are special items that cats leave behind after visiting your yard. To receive mementos, you need to attract rare cats by placing specific food or goodies in your yard. Each rare cat has a unique memento associated with it, which you can collect after the cat visits. Once the cat leaves, check your inventory for the memento they may have left behind.
Mack is described as "determined" in Neko Atsume.
The literal translation of Neko Atsume from Japanese is 'cat collected'.
A game similar to Neko Atsume where you collect dogs instead is Boku to Wanko.
Billy the Kitten and Mr. Meowgi have the highest power level (power level: 250) in Neko Atsume.
Tabitha is described as "leisurely".
Gabriel is described as "diligent".
Patches is described as "jealous".
Princess is described as "ditzy".
Spud is described as "cautious".
Ginger is described as "bashful".
Shadow is described as "peculiar".
Marshmallow is descried as "aloof".