Dayn is not often used as a baby boy name. It is not in the top 1000 names. Out of the family of boy names directly related to Dayn, Dane was the most frequently used in 2018.
Baby names that sound like Dayn include Dain (English), Daine (English), Dane (English, Dutch, and Lithuanian), Dayne (English and Scandinavian), Deyn, Deyne, Daene, Daetin, Daetyn, Dahn, Dame, Damján, Damyss, Dan (English, German, and Romanian), Danh, Danin, Dann (English), Danne, Deam, and Dean (English and German).
† approx English pronunciation for Dayn: D as in "day (D.EY)" ; EY as in "ate (EY.T)" ; N as in "knee (N.IY)"