There are graves in many locations but I find many have little if anything. There is one with some great items but thats about it. I like how the graves have names on them like FO2 but FO2 also had unique items and better weapons and armour in the graves and there were alot more. I am happy grave robbing is back, I was asking for it alot. When I saw the grave yard in the trailer I thought "I can't wait to rob all those graves" then I find out theres only what five? (at goodsprings)
Heh, I remember the funny stuff you could find in the Den graveyard in FO2, as well as the 'Grave Robber' perk you got for opening them.
I always make sure to grab the shovel at the second wellhead in Goodsprings Source, and then whenever I find a grave site I hop back to base and grab it. Not that I ever find much in them, but it never hurts to look.
Aside from Goodsprings Graveyard and Yangtze Memorial, I have also found two grave sites in Novac, next to one of the boarded-up houses. I haven't thoroughly explored most of the Mojave yet so there are probably more I haven't found, but I suspect there are not that many of them in total, especially compared to FO2 which had dozens just between The Den and the New Reno graveyard.