I have the Tiger places (dark green), which I believe contains census designated places. I also have the Census Bureau's Cartographic Boundary Shapefiles - Places (Incorporated Places and Census Designated Places) (light green). Those two basically overlap just perfectly as shown here:
When I look at the same area on Google Maps, the unincorporated community of Aberdeen, California shows up (as well as Blackrock and some others):
Are there any sources out there for unincorporated communities? When I check the USPS zipcode lookup I get a zipcode for Aberdeen, and I imagine I can use something like the Census Bureau's ZIP code spatial data to get an idea of what communities are in what zipcodes, but that really doesn't give me the actual centroid or boundary of Aberdeen.