Trust me on this one

Only one Sally B.
909 is the Collings Foundation bird that flies the country regularly. The CAF has Texas Ranger (Grounded at the moment) They also have Sentimental Journey that flies in natural metal 457th BG markings.
Yankee Air Force has "Yankee Lady"
Also flying are Dave Tallichet's "Memphis Belle"
Doc Hosper's "Chuckie"
EAA "Aluminum Overcast
Evergreen Museums B17G (unnamed)
B17G Fuddy Duddy (just changed ownership)
The newly restored "Liberty Belle" has been flying about a year.
Paul Allen has a B17E he's restoring to flight.
There is a B17F that is flyable, but not flown called "Boeing B"
The well known "Swamp Ghost" a B17E that was sitting intact in a swamp in New Guiniea was just recovered and on it's way home.
And there are lots of gate guardians and museum birds, as well as the original Memphis Belle and another combat vet B17G Shoo Shoo Baby at the AF Museum. And the NASM has the B17D "The Swoose"
Throw in the recovered and restored to static "My Gal Sal" B17E and one recovered a while back from a Canadian river that is being restored along with a couple others and you've got it for B17s. At least what I can recall off the top of my head

There are a couple more in museums in England too