One of the fun things about comics from the 50s and 60s is that our heroes had pets that occasionally helped them out of various jams whilst fighting crime and villains. I read more Krypto stories back then, so he's high on my list of favorites. I saw a few stories about the Legion of Super Pets and I did know who Proty was, but I never read origin stories of Comet, Beppo or Streaky back in the day. I do think my cat Thuvia is a relative of Streaky, though.
I also never have read a single story of Ace, the Bat Hound, though I have seen several of his animated appearances. It's kind of interesting that I don't know of any Marvel heroes having pets, other than the Falcon having Redwing, which was (at least at the time) a creation of the cosmic cube and the Red Skull- their bond, I mean. Anyone know of any other Marvel animals that were pets? Oh, and Lockjaw, though he seemed to have a mind of his own most of the time.
Still, I think my favorite pet/friend is Aquaman's octopus pal Topo. Arthur gets made fun of a lot these days, but he's got some great powers. I do think it's outrageous Topo didn't get to have an appearance in Batman: the Brave and the Bold, even though I liked Fluke the dolphin, Topo would have made a more fun pet.
So, did I miss any pets? I know Green Lantern had an alien friend in his comic for a while, some little plant creature, but Wonder Woman never had one. The Hawks had various birds hanging about, but never any true sidekicks.