Gross question, right? Or perhaps just...stupid? Perhaps, but this is video games and this is the internet, meaning that more than one person has thought about having sex with an Animal Crossing character, and those people have got together.
Auntie Pixelante has combed the depths of a certain niche porn mecca, found everything there is to find about Nintendo's casual role-playing adventure (mostly based on which characters had "images" posted of them), and turned the data into handy little charts. Which makes it science. And science can't be weird.
When it comes to individual characters, by far the most popular was Sable, one of the Able sisters, the town's seamstresses. Interestingly, Sable is the one who all but ignores the player for days, and only begins to get chatty once you've been around for a while and she feels comfortable enough to open up to you.
Second most popular, and this one is no surprise, is Tom Nook. Why? Because some people like it rough, and there is no greater bastard in video gaming than Tom Nook.
Aside from the "regular" characters, the ones who are in everybody's village, the most popular of the randomly rotating cast are the ones who turned up in the Animal Crossing movie. Them and cats. Animal Crossing pervs love cats.
Warning: I've left the full chart's watermark untouched, but know that the link contained in it is very, very NSFW.