These are the ones i can think of:
Plaza Inn-
minnie, chip, dale, hook, tigger, pooh, eeyore, rafiki, fairy godmother, max, and sometimes other characters (piglet has made appearances here! as have the tweedles!). that said, birthday parties ONLY have mickey and minnie. it's just a meet and greet with photos, no autographs
PCH-
lilo, stitch, mickey, minnie, goofy, sometimes max
Storytellers-
haven't been there yet, so i'm not sure who comes out
Goofys Kitchen-
haven;t been here either, but many characters
Ariels Grotto dining
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around the park, for meet and greets, your best bets to see many characters are:
Town Square
Toontown
In front of the castle
Critter Country at Poohs Corner
Tomorrowland by the water ball
Golden State (near that outdoor playground)
Most characters in
Disneyland are considered atmosphere. so you can't count on finding a character in the same spot at all times of the day every day. characters can wander within parameters. so if a cast member tells you that you can find mickey in town square at 5pm, there won't be a specific spot. most characters stay around the firehouse, the flagpole, and the hat shop wall, but you should definitely just look around. But Toontown and Critter Country are primarily photo op locations, so there's a set place to find these characters.
Sun Plaza is your best bet for characters in DCA. You'll see everything from Lilo and Stitch, Mickey and Minnie, Chip and Dale, Donald Duck, Goofy (you will find these characters there pretty much every day), 4 at a time. characters are out all day. if you want to see all of the characters, hang out for an hour and you'll see them all, or all who have come to meet their friends that day.