If we're talking catboys, my mind immediately goes to 'The Rising of the Shield Hero'—Raphtalia isn't technically a catgirl, but her demi-human traits give off similar vibes, and her bond with Naofumi is heartwarming. Then there's 'Tokyo Mew Mew,' which flips the script with catgirls but has such a playful, colorful aesthetic that any catboy fan would enjoy. For pure catboy energy, 'Servamp' nails it with Kuro, a lazy, sardonic vampire who transforms into a black cat. His dynamic with Mahiru is equal parts hilarious and touching.
I'd also throw 'Nekopara' into the mix, though it leans more into catgirl territory. Still, the sheer charm of the anthropomorphic feline characters might scratch that itch. And let's not forget 'Fruit Basket's' Shigure—he's more fox than cat, but his mischievous energy feels feline adjacent. Honestly, the anime world needs more dedicated catboys; they're an underserved niche! Maybe the next big isekai will finally give us a protagonist who's a full-time catboy instead of just a guy with cat ears.