While there are many maps of the individual ferry systems that operate in the Puget Sound, there doesn't seem to be a simple, readable unified map that includes all of them. I've combined all regular ferry service that operates in the region into one glanceable diagram that allows for easy differentiation of operators as well as whether they are passenger-only or also carry cars.
While researching the schedules of the trains that run along what I'm calling the Pacific Northwest Corridor (as a West Coast version of the Northeast Corridor), I realized that I couldn't find an up-to-date combined diagram that showed how frequently all trains run along these tracks, so I made my own.
The simplicity of services along this corridor allowed for a fairly straightforward diagram. That didn't stop there from being a couple oddities, like the fact that Amtrak will only let you buy northbound tickets on the Empire Builder between Seattle and Everett (or won't sell you any tickets on the Empire Builder between Portland and Vancouver, WA).
I'm looking forward to needing to update this as Amtrak and Sound Transit expand service.
I also want to acknowledge this draft of a frequency schematic by Zach Shaner from 2010, which includes California and some additional corridors. It's a useful diagram, though the larger scope means that some details, such as which services begin and end at which stations as well as which agencies operate them, don't end up represented.