Here are some gifts you could give to a girl who owns a cat:

Air freshener: After having a cat for a long time, the room will smell. Giving an air freshener can help freshen the air.
Lint roller: Cat owners often have cat hair on their clothes. A lint roller can help remove cat hair from clothes.
Cat backpack: When taking your cat out, a suitable cat backpack can make things easier for girls.
Cat jewelry: Cute cat jewelry, such as cat watchful pendants and seashell cat pendants, will definitely appeal to girls.