There are averaged scores from various university studies and user reports on the over 800 registered daylilies that were exposed to rust and examined for performance, and those can be searched in the ATP daylily database:
http://garden.org/plants/group...
To pull up all daylilies that have either been in averaged-score studies, or have been reported informally by ATP members, as having a resistance or susceptibility to rust, toggle the "shows resistance" or "shows suceptibility" box shown in the above screen-capture. For very specific university-based averaged scores that are only assigned to those cultivars that were formally observed and tested, you can also search via the numerical toggle. Those score ranges and test sources are explained and shown in a link found at the bottom of each daylily page ("Read our note about daylily rust scores" link):
Another approach is to search back on daylilies' lineages, as well as forward into their offspring, to find related lines that may have contributed to, or follow from, those that carry tested score reports.