An interesting tidbit has been brought up a few times: some characters on the show have four fingers, and others have five. Being slightly curious, I did some research, and now I think I have a somewhat accurate list. Behold:
FOUR FINGERS: Cute Biker Dipper Pines Gnomes Ma Mabel Pines Robbie Sheriff Blubs Tambry Toby Determined Wendy
FIVE FINGERS: 'Lil Gideon Bud Gleeful Deputy Durland Deuce Grunkle Stan Lake Gravity Falls Ranger Lazy Susan Lee Manly Dan Manotaurs Mr. and Mrs. Pines Mystery Man Nate Old Man McGucket Pa Reginald and Rosanna Shandra Jimenez Soos Thompson
UNKNOWN: Mikey R.
Now, I'm not going to suggest that this list is perfect, but I still think it's worth putting out there.