As you certainly all know by now, any distilled agave-based spirit is a mezcal. So under the broad category of mezcal, we have a variety of spirits that are unique in their own right. Also, in the general family of agave-based alcohol, there is pulque, which is derived from the agave but is not distilled.
Beyond tequila and mezcal, these spirits are not widely known, though as the growth of tequila and mezcal continue, I think these spirits may slowly seep into the consciousness of agave connoisseurs. Also, as I get a fair number of questions about these agave alternatives on my blog, Twitter, or FaceBook, I thought a post on this topic would be useful to many. It actually helps me to sort it all out in my head as well. Hopefully yours too!