Sources
X-Wing Data
Most of the squad builders about use XWS as a handy way to import/export data. The spec for this format is still in development, but put succinctly, it's an agreed-upon implementation of JSON. The closest thing to an authority on this format is available here. Command Deck, however, shamelessly borrows from guidokessels. This hub provides a regularly updated repository of relevant JSON for all ships and upgrades, as well as high res images. I'm not forking directly from either of them, but every reference to, or image of a card will be leaning on the fine work of at least these two repos.
Meta-Wing
To understand the purpose of Meta-Wing, you need to be familiar with List Juggler. List Juggler serves as a data repository, and is primarily used to collate tournament results. Tournament Organizers are readily encouraged to update Juggler with as much detail about their events as possible. This provides the community with the ability to analyze the current state of the game, spot trends and problems, and generally get a feel of what is going on in the tournament scene. Meta-Wing "uses the data from the X-Wing Lists Juggler and slices and dices it in a variety of ways.". Having vast amounts of data about the tournament scene is great. Having a handy tool that makes sense of that data is amazing. Meta-Wing, in my opinion, is awesome, and like many great tools this community has spawned, it's totally free.
Command Deck is hosted on Azure, but it's presented via Facebook. It makes sense to leverage some of the data already there. I'm only just learning what it's possible to do with the Facebook API, and so far, I'm intrigued.
FFG
Faily obvious source. Currently, I'm liking to the live page for the latest FAQ, whatever that may be, and whenever it gets published. The downside is that any change to the code on the FFG support and this will stop working. On the plus side, it means the latest FAQ is available here immediately.