Just for completeness' sake, this game did not use cards, but some other games do; all of the following cards partially lift the fog: spy card, reconnaissance card, surveillance card. If you're unfamiliar with them, there's [a page on the WL wiki](http://wiki.warlight.net/index.php/Spy,_Reconnaissance,_and_Surveillance_Cards
) which describes them all.
Also, a much more obscure (and indirect) way to look through fog is with an AI. This is not really documented anywhere (Fizzer mentioned in once [on the forums](http://warlight.net/Forum/Thread.aspx?ThreadID=3423&Offset=0
)), but the AI always uses normal fog to decide its moves. In order to (ab)use this, you'll require a thorough understanding of how the AI thinks. Gaining a clear benefit will probably also require carefully tuned settings.
In most games (especially the ones with normal, light or no fog and/or no AIs; probably a huge majority of all games on WL!) this is irrelevant, so don't worry about it too much.