Darrin sits next to 4 phonetic neighbors — Darren, Darin, and Daron are the closest matches by sound. Most share Darrin's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"great, rocky hill"
"of the Claudian family, lame"
"little king"
"possessor of good"
"bright spirit, shining mind"
"of the Marco family"
"victorious people"
"of the highest power or authority"
"God has remembered"
"gate keeper"
"defender of men, protector of the people"
"people's champion"
"slender, narrow"
"of royal status"
"morning glory, morning well (depending on kanji)"
"free man"
"from the wealthy estate, prosperous settlement"
"God exalts"
"from Tracy, a Norman place"
"uncertain; possibly Romani personal name with regional meaning"
"settlement of Leaxa's people"
Similar sound: These names share phonetic patterns with Darrin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish/Gaelic origins, giving them the same cultural heritage as Darrin.
Rhythm: Darrin is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.