I've run them over with the lawn mower by accident but I can't recall ever purposely killing a frog.
Plenty of birds, used to use bird as target practice for my pellet gun as a kid.
Also turtles. I used turtles as target practice. I actually entirely irradiated turtles from my parents pond back when I lived with them. Would shoot their head with iron sights from across the pond with a 22lr