XDA-Developers is a great community, famous for all sorts of mobile hacking and development but with a particular focus on Android and Windows Phone. It provides great resources and information about all things developer-related, with a wiki and a large forum that has over 4,000,000 active users. It is due to those active developers and forum members that XDA is considered a leader among all dev communities. Most of the custom ROMs ever built are made by the experienced developers over at XDA.
These developers often create apps and software which are not suitable for the Android Market – some of which are even against the Market’s Terms of Service. Here are a few great examples that I find to be very useful and one of a kind. Some of these can be found on the Android Market, but many can’t; all are made by members of XDA-Developers.