Dubberly Design Office (DDO) based in San Francisco is a very intresting office. Alone, going through all their great and informative concept maps will take you hours over hours, maybe days. Also, they collected a huge number of design processes in a book titled: how do you design?

The concept maps and the process colletion are available as PDF-downloads,
what I think is generous – thanks for sharing.

An intresting article about Hugh Dubberly and its love of diagrams can be found on the AIGA website:
“Supermodeller: Hugh Dubberly”