While participating in your highly illegal ROM downloading madness you may come across rom sites which are well organised enough to have codes for the roms. Some are easy enough to figure out, but some are not so easy.
Standard Codes- [a]
- Alternate
- [b]
- Bad Dump
- [f]
- Fixed
- [h]
- Hack
- [o]
- Overdump
- (M#)
- Multilanguage
- (###)
- Checksum
- ZZZ_
- Unclassified
- [p]
- Pirate
- [t]
- Trained
- [T]
- Translation
- [x]
- Bad Checksum
- [!]
- Verified Good Dump
- (??k)
- ROM size
- (Unl)
- Unlicensed
Country Codes- (1)
- Japan and Korea
- (A)
- Australia
- (B)
- Non USA (General).
- (C)
- China
- (E)
- Europe
- (F)
- France
- (FC)
- French Canadian
- (FN)
- Finland
- (G)
- Germany
- (GR)
- Greece
- (HK)
- Hong Kong
- (I)
- Italy
- ($)
- USA + Brazil NTSC
- (J)
- Japan
- (K)
- Korea
- (NL)
- Netherlands
- (PD)
- Public Domain*
- (S)
- Spain
- (SW)
- Sweden
- (U)
- USA
- (UK)
- United Kingdom
- (Unk)
- Unknown country
- (-)
- Unknown country
The following codes are unique to specific systems. - [C]
- Color
- [S]
- Super Game Boy
- [BF]
- Bung Fix
- (BS)
- BS roms (satellite distribution system)
- (ST)
- Sufami Turbo
- (NP)
- Nintendo Power
- (1)
- Japan
- (4)
- USA
- (5)
- NTSC onlu
- (8)
- PAL only
- (B)
- non USA
- [c]
- Checksum
- [M]
- Mono only
- (PAL)
- Euro version
- (Y)
- Year unknown
- (Adam)
- ADAM version
- (PC10)
- PlayChoice 10
- (VS)
- Versus
yerricde says "Last time I checked, the (PD) tag wasn't strictly limited to the public domain but rather to any ROM that has been authorized by the copyright holder for free redistribution. For instance, GNOME vs KDE and Tetanus On Drugs are both (PD) even though they're © Damian Yerrick, released under the GPL." - I guess this is true. I think that Zero Tolerance for the Sega Genesis has been licensed for free distribution in a similar manner, and is classed now as Public Domain even if it used to be commercial.
These codes taken with the a small brown dog's permission from his site at http://www.siteaboutnothing.com.
I have tried to ensure that these are correct, but information is scarce, even on the Internet. Any corrections or additions, please msg me.
Thanks to TheBooBooKitty for pointing out a mistake. | 
