My favorite NPC is Katrina for sure. I love the mysterious vibe that she gives off. She also looks really cool too! I just love everything about her character. I always open up the fortune teller shop when I unlock it on my games, because I just love having her in my town.
Katrina is fun. I like Resetti, although his character in the older games was 300x better than the watered-down version of him in NL. Kicks is cool, although he was cooler in CF. I like the Able Sisters, especially Sable. Her backstory is so sad! Blathers is cool, but again, not as cool as he used to be.
Phineas :3 I like his overly long old man eyebrows. And how he rewards kids for playing outside... even though they're really playing video games inside xD
Celeste! She was the best in WW when the museum had the observatory, and she let you make constellations and sometimes would talk about her brother's bug phobia. Nowadays, she's just a boring souvenir salesperson. Wee.
I have always liked Gulliver the most, with my second favorite being Kapp'n . I like his design and how silly he is! Plus, y'know, he gives you cool free stuff just for knowing geography.
Phineas is my favourite - he's always sweet/pleasant/nice and has something to give me. I see him in the caf? sometimes.
I like Wendell - always pleased to see him in a dream town. A bit of excitement as to what patterns he may have.
Third and its a far down third is Isabelle - its the sarcastic little smile she gives you as you leave the Town Hall that makes me not like her so much as I would other wise.