There are thousands of named daylilys! If you want to find blooming information on one, google Tinkers Garden. That is a huge database with pictures as well. Just type in the name.

I would imagine that like iris, some are good rebloomers in some zones, and not in others.

Here is a good thread at The Day Lily Forum.
What's rebloomed well for you this season?

Be careful...I hear daylilies can be quite addicting.

Maybe you would like some reblooming irises as well. Those too can be addicting.

Sue

Here is a link that might be useful: Other 'rebloom' threads at The Daylily Forum

You will find that most reblooming daylilies require division every three years or so to keep them reblooming. Stella D'Oros will typically rebloom all summer if they are well maintained. However, it is absolutely true that a cultivar that performs wonderfully in one region can be a total dud in another. Your best bet is to buy from daylily growers in your area.