I've stuffed several of my dog's empty Purina Dog Chow bags with lots and lots of plastic grocery bags and whatever other plastic wrapping trash, then duct tape them closed. After a few months I managed to have quite a few bags strategically placed in my backyard to shoot at. They've been able to stop the arrows from my 60# Samick Sage.
One con, though, is that when I first place them outside in the summer time, lots of ants get in them to get whatever dog food residue is left. But after a week or so, the ants are all gone.
As for dog toys, I have a few that belong to my dogs in the backyard. I haven't thought of shooting them til you mentioned it, but maybe I'll try those next time.
And for those who've thought of shooting at Bois D'arc "apples" left lying on the ground, I can say they've left quite a sticky, gooey mess on my arrows when I've shot at them.