Here is where you can find various useful downloads:
Vector grids. These are overlay grids used to help locate a map against the Ordnance Survey grids.
Vector styles. These are saved values for styles that can save a lot of time when trying to achieve a “standard” look to your maps.
Plugins. Special mini-programs can be written to extend QGIS. A large number of individuals and organisations are writing small tools to perform specific tasks - keep an eye out and you will be surprised at some of the things that plugins are being used for. There are even plugins to help write plugins!
OpenData. You can access the full range of free Ordnance Survey here.
Information on this site is copyright Dauntsey Drainage Board. Most of the maps are based on Ordnance Survey OpenData and additionally covered by that licence.