Maps of who does what, who reports to whom, and who you need to keep in the loop.
An org chart is one of those documents everybody needs occasionally and nobody wants to maintain. These templates are quick enough to build that keeping one current stops being a chore, and quick enough to throw away when a structure is only a proposal.
The classic organization chart covers most needs: reporting lines, top down, one box per person. It is the fastest way to orient someone new, and it is worth having even in a small team where the structure feels self-evident to the people already in it. A matrix org chart handles the common case the classic version cannot, where somebody reports to a function and to a project at the same time. Drawing both lines is usually less confusing than pretending only one exists. The inverted org chart flips the hierarchy so customer-facing staff sit at the top and leadership supports them underneath, which is a deliberate statement rather than a neutral one, and useful when you are making a point about how a team is meant to work.
A stakeholder map answers a different question. It is not about reporting lines but about influence and interest: who can block this, who needs to be consulted, and who only needs to hear the outcome. Building one before a launch or a policy change tends to surface a name that would otherwise have been missed until the worst possible moment.
All four are easy to redraw, which matters because these structures change. You can duplicate a map to sketch a proposed reorganisation next to the current one, and share it to get comments before anything is announced.