Addons?

not addons like expansion
but the ones that help you witht eh game like caluclators
in WoW there are lots but ive never seen any for GW are there any?

Can't find links to some other ones, but my favorite is Guild War Freaks. Requires you have .NET Framework to be able to run if you can deal with that.

Has Attribute and skill calcs, maps of all the skills, character planner, etc.
http://www.gwfreaks.com/