The majority of avocados grown in the United States and sold in markets are the Hass variety. However, similar to other fruits and vegetables, dozens of varieties of avocados exist that we rarely, if ever, see or taste.
Whenever I come across another variety, I buy one to try. My latest find (at my local Whole Foods) was a Reed avocado (left in photo), which is larger than a Hass (right in photo) and is green when ripe.
I found the Reed's flavor to be a little mellower than the Hass's and the texture wasn't as creamy. I prefer the Hass, but at least I can cross off the Reed from varieties I need to try.
For photos and information about other varieties of avocados grown in California, click here.