Blockland adventure mode, just kidding. It doesn't exist...
I thought people had completely forgotten about that. I was wrong.

Blockland is 'The game where you build stuff'. Stuff can be anything. Anything has to include an RPG that you want to play.
List:
Medieval: Probably the most common, and often the worst.
City RP: Common, and almost certainly useless unless the host is known.
Family: In my experience this tends to be a freebuild where people scream "Be me <family member>. This happens in freebuilds anyway so I can't really see the difference.
There are more but I can't be bothered to think of them right now.
I have nothing against RPGs in general, although my list seems to hint it. As long as they are hosted and played properly, they're great.