Marshal, Merengue, Stitches, Julian, those are the four that I can name off of my head. There's a sticky in VTP with the tier listings (not sure if it got taken down though), with top tier 1 being the most paid for / most popular.
Rosie has been the face of the franchise since its anime movie. She's extremely popular in Japan, not sure how popular she is in America, but on the last Animal Crossing poll, she was the highest villager (only counting ones that can actually LIVE in your town by choice, which excludes Isabelle, Nook, Blathers, etc since we all get them).
Oh my gosh I'm dying of laughter. The way you spelled popular has made my day. XD
As others have said, there's a list in the Villager Trading Plaza of villagers based on pupulairiest villagers. The ones that have always seemed to be pupulairiest is Marshal, Rosie, Diana, Beau, Ankha, Lolly, and Merengue.