In the foreground, Agave geminiflora. In the back, Agave americana.
Agave parryi var. parryi. There's also a A. parryi var. truncata for dry climates.
Both of these are quite beautiful and should be available in southern areas.
Agave desmettiana 'Joe Hoak'. This is a very difficult agave to grow in Houston and it's challenged my patience to the limit. This one is two or three years old and still pretty much a baby. I've not given up on it since it is so unusual.
Do you have a difficult plant that you haven't given up on? I'd love to know.