Xerxes

Redump.org is, in my opinion, the most valid of all online databases for game data, so I would consider Redump close to the game's cover in validity. When you can't find a cover and don't have the game yourself, this is the next most verifiable source. It also includes some nice formatting to help you out, like showing region flags next to the IDs in the database and telling you the languages of the games to pinpoint where European IDs had their release. Redump's main flaws are a) it uses the same four character prefixes as game covers do, and b) it only includes GameCube games, no Wii data is available. On top of having only the four character prefixes of the game covers, it doesn't actually include any publisher data like the cover does, so piecing together the last two characters is even harder. In conclusion, use Redump as a check for weird GameCube IDs from GameFAQs or GameTDB, but don't rely on it as a main source.

 

This will be your primary source. GameTDB is huge and contains almost all GameCube and Wii IDs and covers, along with some other miscellaneous data like game languages similar to redump. The problem though is that GameTDB is not as reliable. There are invalid entries on GameTDB, low resolution/wrong covers making it hard to check entry validity (___X__ region European IDs having ___P__ region covers as a consistent problem), questionable developer and publisher information, etc. The actual IDs though are generally correct, and this is the only source other than a personal dump that contains full 6 character IDs like the Dolphin wiki uses. I would say the IDs from GameTDB are around 90% accurate, with the other 10% generally being flat-out missing IDs or false entries (for example wrong publisher code). Because this is pretty trustworthy but not perfectly so, I still recommend checking against one of the more reliable sources above before mindlessly posting IDs from GameTDB onto the wiki. However, in the case of a Wii game with no good cover scans for example, this becomes the most reliable source and there's no choice but to trust it until someone with the game comes to confirm/deny your addition.

 

There is another problem which is a bit more subtle; while GameTDB is a good source for Virtual Console IDs, since GameTDB contains IDs from other Nintendo consoles, if a retro game had Virtual Console releases on multiple consoles, the actual pages on GameTDB (at least at the time of writing) don't distinguish at all what console that ID is for. So for example if you wanted to find the Super Mario Bros. Virtual Console ID for the Wii, but the game also had a Virtual Console release for the WiiU, you would get both the Wii and WiiU Super Mario Bros IDs in your results if you use the general search with zero way to distinguish them, so be careful about that and try and double check with GameFAQs for Virtual Console if possible. On top of this, although GameTDB uses the six character GameIDs, they omit the last two characters from WiiWare/Arcade games. While this isn't a problem for Virtual Console, as you can simply fill them in, WiiWare and Arcade games actually do go by publisher apparently for the last two characters in their ID, which means you'll have to fill them in manually.

Now this is a little tip to really help you get the best out of GameTDB. The way that the website is organized, every single ID has a neat little set of links at the top that allow you to go to the next or previous ID alphabetically. At first this might seem like an oddity but it's one of the best features of the site. This will sometimes start you down trails of investigation that can lead to finding out that, for example, the wiki erroneously contains two separate pages for the same game. The thing about multi region releases is, they often don't share a name, so sometimes overseas if a publisher is not clear that it's the same title, databases can get confused and list them as separate. However the IDs don't lie (or at least they haven't so far to me anyways), and when you find two IDs with the same 3 character prefix but different region and name, with two different pages on the wiki, this generally means that it's really the same game in disguise. If you put in the time to prove that they're the same title, and can get someone else to agree with you, then feel free to merge the pages. The one flaw with the next/previous ID system is that GameTDB lists hacked IDs in along with their normal IDs, so for very popular titles like New Super Mario Bros. Wii for example, you'll have to go through a ton of page loads to get to the real IDs. In these situations, try and use their .txt inventory of all IDs instead, which you can get [http://www.gametdb.com/wiitdb.txt?LANG=ORIG here] (starts download).

I'm not going to lie. GameFAQs, on the whole, is a terrible place to get IDs. But as I do recommend looking into release data for games while you do this, you'll usually go to GameFAQs anyways as their release information is extremely good. The rule of thumb here is, never trust their retail GameCube or Wii IDs. The first three characters are all you can get from them; not only do they omit the publisher code again, they also just fill in the region code by the region of release, NOT what the ID actually is. So do NOT blindly trust the region codes from GameFAQs; instead check their uploaded covers instead. In contrast to this though, their WiiWare and Virtual Console IDs are generally pretty good and trustworthy, so if you use GameFAQs for anything, use it for those kinds of IDs and nothing else.