@Petronius here's a large lists of plants for naturalizing. https://www.almanac.com/content/best-bulbs-naturalizing
@Gail-Steman, Thank you for the list. What perennials that grow directly from roots that would be good for naturalizing?
Hi Petronius...I give you the links as my garden is limited regarding plants https://www.gardenersworld.com/plants/10-perennials-to-plant-bare-root/ https://www.gardeningknowhow.com/ornamental/bulbs/bgen/naturalizing-flower-bulbs.htm
Any perennials hardy in your zone are candidates. "Naturalizing" is a term usually used in relation to bulbs, especially in regard to adding them to mowed areas, like Anemones and Muscari that complete their bloom show before lawns in those areas need to start to be mowed for the year. In regard to perennials that are not bulbs, I think ground covers if I hear the word naturalize. Is that the kind of plant you were wanting? Your profile does not have a zone or location, so it would be difficult to make specific suggestions without that info.