Ketsurui Zaibatsu
Samurai:
See here
Workers: White shirts with red pants, black belts, black shoes (or civilian clothing).
Power armor: white above the waist, red below. Black line at midsection. (Samurai armors have silver (and rarely, gold torso and silver arms) instead of white).
PNUgen
Black (sometimes blue or gray) jumpsuits with PNUgen patch, or suits and lab coats.
Star Army Intelligence Agency
As a part of the Star Army, SAINT members wear Star Army uniforms, expect for secret agents, who will wear other clothing as needed to conceal their identity. Spook ships tend to carry all-Black Mindy armors.
Yamatai Security Agency
Male: White dress shirt with blaze orange upper half (white sleeves), dark blue pants, black boots with white shin covers. Black necktie. Golden rank pin/badge.
Female: White dress blouse with blaze orange upper half (white sleeves), dark blue pleated skirt with white pantyhose, black boots. Black ribbon tied on neck. Golden rank pin/badge.
There is no common ID card (although a KS card can act as one, because it knows if the person holding it is the right person)--KS cards will also function correctly in anyone's hands. For example: If Hanako gives her KS card to Kotori, it will act as Kotori's KS card and can identify Kotori while in Kotori's possession.