I think it's just Chevre and Bill from what I can remember. I think they were my starter villagers in new leaf and they're also in my town in wild world which is pretty neat.
At this point, both Filbert and Ankha. Both have been fixtures of my New Leaf towns throughout the years. I wouldn't have it any other way too. Such awesome villagers.
Flurry, Chief, and Shep have lived in my New Leaf town since 2013.
Last time I checked my City Folk town (probably about a year ago), Lily was still living there. She was one of my starters when I first got the game in 2010.
Rosie has been living in my town for the longest time since she was one of my starters, and is still living in my town. If I remember correctly I started playing New Leaf in January in 2018, so it's been a bit over a year.
Julian has been with me the longest. He happened to move into my town a few days after I started the game. I thought he was pretty cool, but I didn't realize how popular he was until I started checking on the forum for other villagers.
On ACWW I had Alfonso for like 3 years. He was such a main character it was amazing. Then, to my surprise, when i started my first ACNL town, I had him as a starter. My feeble mind thought it was a sign XD
In all my towns in NL I always had Whitney for some reason. So now that I have her card I will keep her around even in my new town. I just don't see not having her an option.
When I was in middle school, I had Bob is my WW town (he?s still there, I just dont play anymore, so like 14 years lol). His house was right next to mine and I bordered our two houses with designs and planted hybrids between them. He?s always been my favorite.
I have had Leonardo (jock type) in my town since the beginning, for two years. He?s asked me 6 times to leave and I can?t get myself to let him leave because it wouldn?t feel the same without him! There also aren?t many jock types I like in the game.
In WW, definitely Octavian and Wolfgang. They've been in my town so long, I can't remember when they first moved in. I was lucky, I decided to randomly pop in WW and Wolfgang was thinking about leaving. That was a hard no, made sure he stayed. I love my cranky villagers.
In general, Dizzy has always been a constant in my towns. I first had him in Wild World, then he was in my very first town Kenka and now in my main town Tinytree. In Tinytree the longest villager I've had is Pudge, who was one of my first 10 villagers. In Borei it's Blanche, who was also a starter. Both Pudge and Blanche have their houses right next to my mayor so I have a soft spot for them. They're always the first villager I see when I load the game!