From Nookipedia, the Animal Crossing wiki
Blanca is a recurring main character in the Animal Crossing series. Blanca is a white cat who asks the player to draw her a face. In Animal Crossing, she will randomly appear on the train when traveling to other towns. In Wild World, after turning on the "mysterious cat" mode with the telephone and using Wi-Fi, Blanca may appear in the player's town. If the player doesn't draw her face, she will stay in their town for a while, therefore keeping out any visitors. In Animal Crossing: New Leaf, she only appears on April Fool's Day.
Gulliver is a seagull explorer. In Animal Crossing, he's a sailor who washes ashore on random days. When the player wakes him up, he confesses that he fell overboard in the course of a heroic struggle (the exact nature of the struggle changes with each visit, and as later conversation reveals, all his heroic tales are colorful lies). In City Folk and Wild World, he pilots a UFO on a random weekday, which can be shot down with the slingshot as it crosses the skies. The player must then help him reassemble the pieces of his damaged space ship. He is very friendly and approachable, but tends to ramble and therefore may become boring. Each time the player helps him, he will give away a rare, exclusive furniture item. The UFO has been known to enter town when the minutes on the clock end in 2 or 7. In Animal Crossing: City Folk, the UFO seems to only fly through a town within the first 10 minutes of an hour [confirmation needed], and takes around 25-30 seconds to leave at the other side, at a rate of approximately three tiles per second. In Animal Crossing: New Leaf, Gulliver returns to being a sailor, washing up on the beach as before. Once woken up, Gulliver will give the player clues about a country he is visiting. If the player correctly guesses which country he is talking about they will receive a rare Gulliver item in the mail the next day. If the player says the country wrong, then Gulliver will give the player a chocolate coin.
Joan is an old female boar who comes to town every Sunday morning to sell her turnips. In Animal Crossing: Wild World and City Folk, she has two types of turnips for sale: red and white. Red turnips are sold as seed packets, which can be planted in the soil outside, and which must be watered everyday, although too much watering will ruin them. Only one red turnip is available for purchase each week, and costs 1,000 Bells. The longer it is cared for, the bigger it grows, although it will rot after seven days. They can be sold to Tom Nook. The bigger it is, the more money he will pay. White turnips are sold in bunches, and are used to trade in what the animals refer to as the "Stalk Market." Tom Nook buys these turnips for prices that change from day to day, and every morning and night. Both red and white turnips will rot at the end of a week. However, red turnips that haven't been planted in the ground are exempt from rotting, and in Animal Crossing: Wild World, by placing a bundle of white turnips on a table inside the player's house, they can be kept them from ever spoiling. Note, however, that time-traveling, or traveling to a town that has a different time setting, may cause any turnip in the inventory to spoil. In Animal Crossing and Animal Crossing: New Leaf, Joan sells white turnips only. In Animal Crossing: amiibo Festival, Joan comes on Sundays and sells turnips for a fluctuating price, only in bunches of ten. From Monday to Saturday, the "Stalk Market" will be open and the player has an opportunity to make a profit of bells by selling them, although if prices are low, the player will lose bells. Joan returns the next Sunday and the process repeats.
K.K. Slider can be found playing music at the Roost (Animal Crossing: Wild World and Animal Crossing: City Folk) every Saturday after 8:00 pm until midnight. He is a white dog with large, black eyes, and is always holding his guitar. In Animal Crossing: New Leaf he becomes a DJ and plays at Club LOL every night with his DJ mixes. Saturday night is the exception; he plays his normal acoustic music then.
Kapp'n is the first person that is met in Wild World. He drives the player to a new destination in his cab, helping to determine the name and gender of the player, as well as the town's name. Unfortunately, he may never be seen again in Wild World, unless the player happens to bump into him in the Roost. However, in City Folk, Kapp'n can be seen as many times as the player wishes, because he is the bus driver who drives to and from the city. If the player is a girl, he will take quite a liking to her. In Animal Crossing, he can be met by connecting the Game Cube to a Game Boy Advance via connection cable and going to the dock. He will row the player to and from a small island, singing a sea shanty as he does. He operates the boat in Animal Crossing: New Leaf as well, but charges 1,000 Bells for the round trip. Kapp'n additionally appears in Animal Crossing: Happy Home Designer as a special amiibo Card.
Lyle can be found in Wild World every Saturday, trying to sell insurance. The best thing to do is to just ignore him. He is a weasel who wears glasses. In City Folk, he will be found in the HRA Building in the City. He seems to hate his new job, but helps the player with anything that pertains to the HRA. He retains this job in Animal Crossing: New Leaf and works inside Nook's Homes on Main Street. He returns in Happy Home Designer, being an employee at Nook's Homes and the inventor of the amiibo phone.
Pascal is a philosophical otter, who visits the town on random days giving out furniture. In Animal Crossing: Wild World, he will appear on the beach, and will give the player an item of furniture for talking to him. In Animal Crossing: City Folk, he appears on a random town bridge over the river, where he trades pirate themed furniture for a scallop after talking to him with one in the inventory. He does not accept white scallops. Otherwise, he gives a piece of deep, philosophical information and floats downstream and out to sea. He can be found from 6 am until sometime after midnight. Once he floats away, any other players living in town will not be able to get an item from him. In Animal Crossing: New Leaf he can appear if the player catches a scallop while diving. He will immediately ask the player to give it to him. If the player accepts, he or she will receive a piece of rare furniture.
Pete is the mailman for the village. In City Folk and New Leaf, he can be seen walking around the town at around 5:00 pm, or sometimes when Nintendo sends letters, he will appear outside the player's door as he or she exits the house after loading. In Wild World, to find Pete, the player has to shoot him down with the slingshot (he will be seen flying in the sky at a different time each day). He is in a love triangle with the two pelicans, Pelly and Phyllis, the sisters that work at Town Hall in some Animal Crossing games and the Post Office in other Animal Crossing games.
In Wild World, Redd will visit the town on a weekly basis. He can be found in a large tent placed on the stone area in front of the Town Hall. The player cannot enter Redd's tent unless he or she recites the password. Villagers may reveal the password to the player on the day of Redd's visit. Every visit, Redd will have two pieces of furniture and a painting for sale. Only members can purchase items in Redd's shop. Redd can sign up the player as a member of his "family" for 3,000 bells. Redd is notorious for selling furniture for twice as much as Nook's price and counterfeit paintings.
In City Folk, Redd has established a store in the city. The only way the player can enter the store is to receive an invitation from a villager. Once they are a member they will receive invitations (upon buying an item) to send to others in town. He also refers to the player as "cousin."
In New Leaf, the tent returns and Redd sells art only. Fakes have noticeable differences to real paintings and sculptures. Redd will now mail a purchase to the player, who may only buy one item per visit.
Saharah is a camel and visits occasionally on random weekdays. In Animal Crossing, the player can trade money with her for rare carpets. In Animal Crossing: Wild World, she will ask the player to make deliveries to special characters such as Tom Nook or Blathers, and will give out a reward when the deliveries are completed. In Animal Crossing: City Folk, she will ask the player for either Old Wallpaper or Old Carpets. When she is there, the player can talk to villagers and ask for old wallpaper or carpets. Only a minority of the villagers will have anything for the player. Giving three of these items to Saharah will result in achieving a rare and exclusive wallpaper or flooring. In Animal Crossing: New Leaf, the player can pay Saharah 3,000 Bells. Doing so will cause her to redecorate the player's house with a new wallpaper and carpet. Saharah can install regular walls and carpets in additions to Saharah exclusives.
During the winter season, two small balls of snow will appear daily. If the player kicks the snowballs across the snow, the snowballs will increase in size to the point where the player will have to push the snowballs around. If a snowball large enough is pushed near a larger snowball, a snowman will form. Upon creation, the snowman will comment on his build. If a snowman is created with perfect proportion size of his body and head, he will send a letter with a special present attached. While the snowman will remain in the spot where he was built, he will eventually melt over the course of a few days. In Animal Crossing: New Leaf, there are four different types of snow person and each gives different items.