I made this back in 2010, but never managed to collect pictures of all the dogs until now. Every time I went back and played through Fallout 3, I have intended to take all the screenshots and upload this mod. It only took me 4 years to actually do it.

This mod adds some dogs to the Capital Wasteland, mostly strays. There is a mother and two puppies in Megaton, two dogs guarding Arefu, three dogs in Bigtown, a mother dog and pup in Caterbury Commons, a dog in the Ranger Compound, an irradiated (ghoul) dog and two puppies in Underworld, and a mama dog and puppy in Oasis. Also, three NPCs now have their own puppies.