More irises fit this category in areas with longer growing seasons, but two that are reliable most places are SDB Baby Blessed and TB Immortality. Some beardless irises exhibit extended or repeat bloom as well, e.g., SIBs Lavender Bounty and Reprise. My tall bearded irises sometimes fall over. This is one of the possible problems with TBs. The main things that lead to it are the variety, the weather while the stalks are growing, and the weather when the flowers bloom to catch the rain and the wind.
Some people say that the nutrients in the soil, especially the potassium, are a factor too.
Clumps at their peak do tend to produce taller stalks and more and larger flowers, which together can outpace the increase in stalk strength. Finally, shade on one side can cause a plant to lean, which can contribute to the problem. One thing that hybridizers strive for are stalks that will stand up. These irises, and maybe yours, are best grown in protected areas or by people willing to stake them. Or cut the fallen ones quickly before anyone sees.