Agile requirements - setting the context

Still in the series of posts about requirements related artifacts - previous post. When I say requirements related, I mean something that assists us in understanding the system under development. As in past posts, the user story, scenarios & tests are all part of the requirements package. What else is there? What other kinds of things can we produce that add value & enhance understanding. As a coach many times when working with a new team, I'm listening to the conversation and I get lost. There are too many applications, acronyms, systems for me to understand what's going on. When I'm lost I almost always ask the team to allow me to draw a system context diagram.