Fascination II is one I always marvel at for its many varied bright magenta tones on white. Connell's Dahlias has that, and be mindful of Fascination vs Fascination II to assure you're getting the right one.

There's another collarette I've since lost that I used to like very well. If I think of it, I'll post later. Busy time of year!

:0) Phyl

I've thought of another collarette which was from the Impression series, Impression Fantastico specifically.
2.5" flowers in dark purple with white collars and tons of blooms, although only on 9-12" stems.

Jackolantern was the only other one I've grown, but the colors vary so much, I wanted something more reliably uniform.

Phyl, I didn't answer your earlier question on the already-blooming one you bought: yes, it will likely produce tubers and yes, you can save them as you would any other dahlia tuber (which means about 40 different methods to choose from. Good luck with that!) I'm so sad I killed my Pooh tubers..... next year perhaps I'll get it back.

Best luck with your new flowers!