I particularly like Shocker Lizards
I've always loved Shocker Lizards from the moment I first laid eyes on them. I wanted to make a wizard who had multiple shocker lizard familiars, but never got the chance. :/ I did however make some monsters which were based on them (skeletons with different types of metal plating, making them walking batteries. They were basically re-skinned shocker lizards, including the ability to zap eachother and make a super shock).
I don't know if they qualify, but Chuuls are one of my favorites. NEVER go into a swamp on a flat-bottomed boat if I'm DMing you in a game...
a chuul was in one of the Xen'drik expedition adventures. Only time I've ever faced one, and I've never used one. A shame, I agree with you that they're pretty sweet. I'm gonna have to change that...
Do blink dogs count? I rolled them as a random encounter once, and they've had really great traction in that game anyway.
In a game a while back, the DM had random encounter chart he made himself. One day we rolled on it and ended up getting a blink dog companion.
Then sometime within the next 2-3 rolls on it (and we made at least a few a night), we rolled the same thing. It was like a 96-97 to get it. Bastard made us re-roll, saying he hadn't had a chance to refill that slot yet. We so got cheated out of having two blink dogs.
I'm sure I'm in the minority, but I don't think I've ever fought any giant of any variety. I don't think I ever even fought a troll in 3rd edition...
Oh, here's one: displacer beasts. I loves 'em, and I don't know how much lovin' other people give 'em but it ain't enough! I want to make a harness for my (black) cat consisting of a spare pair of legs and some tentacles to turn him into a displacer beast... Then follow him around with one of those invisible dog collars off to the side of where he's standing.
