After visiting a number of northern California cemeteries, I've found a lot of marker shapes and ornaments that are common. Sometimes they are a bit different, depending on the maker, but I wouldn't notice except when comparing photos of them. There are also custom or homemade markers, but those are destined for another blog post someday.
Other markers are very different. They're not one-of-a kind, but often unique to a specific cemetery. They seem to be commercially manufactured, but for some reason or other weren't popular. Here are a few that I've found recently.
Arrowhead. Sebastopol Cemetery
Cradle for an infant. Cloverdale Cemetery
The arched marker is for two children. Cuffey's Cove Cemetery.
A whole family of "unique" markers in Little River Cemetery
I've seen a goodly number of Gates of Heaven carved into a marker, but this is the only stone I've seen that is shaped like gates. Evergreen Cemetery, Mendocino.
Cradle for an infant. Alamo Cemetery
Lafayette Cemetery
Hopland Cemetery
Another cradle-like marker for an infant. Little Lake Cemetery, Willits