The signs from where I live in New York:
Hudson Falls: spell H-F
Glens Falls: spell G-F
Fort Edward: spell F-E
Lake George: spell L-G
Kingsbury: sign king with the K changing to a Y
Queensbury: sign queen with the Q changing to a Y
Warrensburg: have one palm face up and tap W on it a few times
Saratoga: sign race with the letter S
Albany: letter A in a 7, which I see at home, or sign government with A, which I saw once at RIT
Rochester area:
Rochester: letter R in a 7, I had a roommate from Virginia who used the same sign for Richmond
Irondequoit: sign for idiot repeated a few times
Toronto: sign breasts, I've never figured out why they sign it like that, anyone know?
New York city: same as the state, but spell NYC if confusion avoidal is desired
States
Florida: I've seen the F moved down cheek and spelling FLA, I've also seen holding out an arm and moving a F from wrist to elbrow because of the Florida peninsula
Massachusetts: I've seen spelling MASS and signing with the letter M changing to S while sliding over the chin
Countries
Egypt: letter X in middle of forehead, from the cobras on ancient Egyptian masks and statures
Russia: sign dry then move down to make a big 7
Italy: use letter I to make little cross in middle of forehead
India: press middle of forehead with letter A and twist a bit
Malaysia: hands are open besides the head with palms facing the cheeks, move hands up and down alternately a few times, I learned this from a roommate. We both knew someone from Malaysia and I saw him use the sign himself.
China: point to Mao coat buttons on body in a big 7. Is there any other sign widely used? Mao is long since dead. My mom showed me the index finger on letter G sign, which was mentioned in this thread. I showed it to somebody from China, but he didn't know it because he didn't learn sign at home. He was happy to see the sign.
Canada: letter A near shoulder and pull a few time as if pulling on shirt
Mexico: make 1/2 of a moschute curving up. Is there any newer sign?
Korea: sign head, but backwards from ear level to top
Vietnam: use index finger and thumb to make a V beard on chin, or was it an upside down V starting from the upper lip?
Thailand: like Greece or Rome, but with index finger sliding down nose instead of tracing out a big nose
Afghanistan: bent hand shape moved in circles a few times near the side of the forehead. I saw this only once.
Norway: N moved in circles by side of forehead
Denmark: like Norway, but with D
Sweden: like pet, but like lifting a fold upwards or petting a mountain peak
England: hands are facing down and one is holding the other like 2 people on a walk hold hands, pull the hands toward body
Germany: both hands go from fist to 5, with palms facing sidewards and one hand on top of other
Israel:letter I slid down chin a few times
Antarctica: a palm faces down and letter A with thumb pointing up at palm is moved in circles