There is a custom based in Talmud Yerushalmi for Jews to be stringent during the Aseres Yimei Teshuva to eat bread that exclusively Pas Yisroel. Even those who generally do not make a point to eat Pas Yisroel are encouraged to accept this practice during the period between Rosh Ha-Shanah and Yom Kippur.
The Star–K shares more information about which foods are subject to Pas Yisroel (PY), and you can find PY items from the OU and Kof-K here. Some PY products you can find locally are shared below:
– Aldi: Specially Selected breads (Scroll K)
– Trader Joe’s: Chocolate Brooklyn Babka (OU), Half Moon Cookies (OU), Organic French Baguette (MK), Challah – Braided Egg Bread (Earth K)
– Kroger & Target: Food for Life Ezekiel Sprouted Grain Breads (Kof-K)