I will list a MDB and a few SDBs first. I live in zone 7a. We have dry summers that bake the soil when even weeds die and winters that get into the teens and single digits only every few years.
First there is a MDB Trimmed Velvet. I got this one at the CAIS plant swap in the spring. brought it home and planted it in the hot sun. It bloomed in the fall and has bloomed every spring and fall since.
Here is Betsy Boo, SDB. Not an outstanding bloom but reliable bloom every spring and makes a nice clump. Requires no care and blooms in mostly shade or sun.
This is Making Eyes, SDB. Just ignore it and enjoy it in the spring. It can fend for itself.
Another SDB, Stitch Witch, that will take care of itself. It will bloom and makes a nice clump.
This is Sun Doll. Beetles nearly killed it this spring before I jerked it up and looked at the roots. I pulled the beetles off and stuck it back in the ground. I will be very surprised if it does not re-bloom this fall. It is looking good now. No treatment except to kill the beetles
I will list a few other classes later.