any drag and drop scripts

Are there any scripts available that allow you to easily have a libary of obejcts from the curret file or select files plus everything thats attached to them ie armatures, game controls and actions etc. So that you can simple view them all and drag what you need into the 3d window. This will help heaps for creating worlds for games. I hope i explaned it properle. I am pretty sure that ages ago i used a script like this. It will be easier then appending and haveing to always duplicate all parts of obejcts.