Dillion sits next to 3 phonetic neighbors — Dylan, Dillon, and Lillian are the closest matches by sound. Most share Dillion's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"sea tide, son of the sea"
"fair one, bright, handsome"
"a jewel-bright, exotic feminine name"
"righteous, virtuous, pious"
"daughter of the sky"
"cosmic order, the world as a harmonious whole"
"courageous, spirited"
"industrious"
"son of the noble one"
"water of life"
Similar sound: These names share phonetic patterns with Dillion — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh origins, giving them the same cultural heritage as Dillion.
Rhythm: Dillion is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.