Dylann sits next to 3 phonetic neighbors — Dylan, Dillon, and Dillan are the closest matches by sound. Most share Dylann's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of the wave, born of the sea"
"from the southern lands"
"dwelling, honor"
"Western cowboy hat, frontier spirit"
"benevolence, humaneness"
"heart, mind (from Hugh root)"
"who is like God"
"lord, have mercy (liturgical)"
"strong, firm, enduring"
"divine gift (blended)"
"God is beautiful"
"from the Liffey valley"
"the new house"
"royal power"
"roe deer wood"
"settlement by the brushwood"
"gentle, tame"
"guardian of riches"
"enduring, lasting (via Dante)"
"son of Jack, God is gracious"
Similar sound: These names share phonetic patterns with Dylann — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh mythology origins, giving them the same cultural heritage as Dylann.
Rhythm: Dylann is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.