Provide a collection of simple tree layouts

This issues is migrated from the wishlist HTML page at https://graphviz.org/doc/todo.html.

Git blame shows this is from 2014:

620a8b3427 (Emden R. Gansner 2014-01-30 15:21:11 -0500  79) Provide a collection of simple tree layouts.

I'm not sure if this is talking about a gallery of tree graphs? Or a set of ways to lay out a given tree?