If you're looking for manga similar to Felix no Mei Tantei, you might like these titles.
Rosette Ashbery, a human girl, works as an assistant to Raymond Sherman, a Siamese cat who runs a detective business at the mansion her father owns. Set in a mysterious metropolis where crime is rampant, the deductions of a cat detective are clear!
Not all cats are the same, but they're all lovable and cute in their own ways. In this autobiographical series, Ikuemi-sensei takes us through the Ikuemi family's long history of cat parenting, starting all the way back from their cat "king," the majestic Kiyo.