Yep. Like Maxie said, Land dragons do a whopping amount of damage, but they're slow and don't fly. Earth shakers are also good. However, adult dragons on do 1/3 of a bar, not 1/2 or 3/4 like some other prey, and I believe blue dragons do about 1/4.
Personally, my favorite pet (that's worth gold) is the shark - which is sold at the shops for 5 gold. It flies, attacks rapidly, and deals half a bar.