Diagram: SQL Indexes

Inside the SharePoint Dungeon - Diagram: putting it all together

Diagram: Query Rules, Result Blocks, Result Sources

SharePoint Physical Architecture Design Diagram

Here is a template used for SharePoint physical architecture designs:

SharePoint Information Architecture Diagram

Here is the template I use for Information Architecture designs. It's built using Mindjet and I flesh the nodes out with the low level detail to build a comprehensive and easily readable document - some of the nodes on this one I've already started populating with the customised/third party solutions being used at this site (see Site Definitions, Records Management etc) - you get the idea - it grows...

Could also add Search top level node to this

70-332 Planning the SharePoint environment