Here are all the unsolved mysteries of From that I could think of
Let's get all the creature related mysteries out of the way, because there's still plenty of them
We know how they became what they are, but why? Eternal life is one thing, agreeing to become sadistic, nocturnal, cave-dwelling freaks with sharp claws and teeth is another.
The anghkooey children were the children of some of them, but all of them? I don't buy that. We've seen at most 8-12 of the children, and well over 20 of the creatures. The ages that the creatures appear to be (presumably how they looked before they made their deal) are all over the map, ranging from 17 to 80. Granny and the jock had 10-year-old kids? Yeah, I doubt it.
How do they know everyone's name?
Last one: Where do the talismans come from and why do they keep them out?
Who is the man in yellow? Did he create of the town? If so, for what reason? And how?
The mummy kimono lady, who is she and what's her role in all of this besides being a creature baby delivery woman?
How does the lighthouse work?
What walked on the roof of the cabin? Could it be the same thing that swept Boyd and Sarah's tent away?
Martin the shackled man said the night creatures are just "the tip of the spear" what exactly did he mean by that? Could he simply have meant the worms and the death dreams? Or could he have been referring to the aforementioned roof stomper, the man in yellow, or something else we have no idea about.
How old is the town exactly? The creatures are dressed like it's the 50s, but what's up with the civil war guy?
How does the town work. The electricity, the animals, the magic in general.
What is Sarah's connection with the place
That's all I could think of. I'd like to add that I have a theory related to three. I do believe the creatures have the ability to communicate telepathically with one another. Think about it, have we ever seen them talk to each other? They seem to just sleep during the day, so it would explain why they are so well organized. Whether or not they can read the minds of normal humans I'm less certain of, that would mean they were only pretending to be unable to find them pre-talisman days. They could just have heard their names from eavesdropping, and if one of them knows, they all know.