Ankha is obviously very popular. I personally like Lolly and Rosie very much. I just think they both look really cute. Also I had Lolly in my previous town and I loved her!
For yourself you should maybe also think about what personality you want in your town.
I love Lolly cause she's freaking adorable! But I also like Felicity. I have Ankha and Rosie in my town as well, but Felicity and Lolly are probably my favorites.
Katt is my favorite cat villager. Ha, try to say that three time in a row. I have had her for the longest time and she is the first villager to give me her photo. We're bros. xD
My favorites have to be Merry, Kid Kat, and Lolly. But honestly I like all the cat villagers even if they don't look cute/don't have a great design because I love cats. They're basically my life. (this is probably what happens when you grow up around 7 cats)
Felicity lived in my town for a while. She was a void from my boyfriend's town. We both adore her, myself probably more so, but we were each after a different peppy. I personally find her design to be the sweetest without any distracting features. If I had to choose a kitty for my town, it would be her.
Katt! I just love her, I think her design is awesome (those yelllow eyes, those cute little fangs, those cool stripes!) and she's one of the few uchi's I like having around.
Lolly! She was in my first 5 starter villagers so I'm probably saying because I like the fact that she's always been in my town, but she's super cute, fits the cute theme of my town and is just really cheerful
Ooh hard choice, my top 3 favorites would be Lolly, Olivia and Rosie, but I'd have to say Lolly is my favorite because I like normal villager personalities best