Watch any of last year's SpaceX LEO satellite deployment missions's broadcasts in YouTube, and you can see views from at least several different cameras. At least two on the 2nd stage nozzle, at least one on the payload, at least one on a gridded fin, one in the 2nd stage LOX tank, and I suspect there are many more.
The cameras serve several purposes, possibly including marketing and HR/recruiting, but primarily they are used to collect additional information about the flight.
Question: Roughly how many self-viewing cameras are present in a Falcon 9 LEO mission?
Details may be confidential or proprietary, but are there closer to a dozen or a hundred? Closer on a log scale or linear?
above: Frames from the broadcast changed to monochrome (R+G+B)/3 and stitched manually into a GIF. From When this F9 2nd stage engine suddenly moves upon shutdown, is it moving along the rocket's axis? (currently no accepted answer).
above: GIF (from giphy) of (probably) SpaceX's CRS-5 Broadcast, from here (giphy's limit is 15 minutes). See SpaceX CRS-5 Launch: What is the footage that appears to contain bubbles?