Narrated Abu Huraira (RA): I heard the Messenger of Allah (ﷺ), say, "If one of you sneezes, the person next to him should say, 'Yarhamukallah'; "If you sneeze more than three times, you will understand that he has a cold. So you don't have to say 'Yarhamukallah' after three times.”
Source: Sahih (Albani). Silsilah Sahihah: 1330
Duas from IslamicAPI's Masnun Dua dataset (based on the Quran, hadith, Hisnul Muslim and Rahe Belayat). See the dataset