Flynn sits next to 4 phonetic neighbors — Finn, Glen, and Wynn are the closest matches by sound. Most share Flynn's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of the red-haired one"
"God is salvation"
"son of James"
"son of the firebrand (short for Tyson)"
"water, thermal waters (place name)"
"who is like God"
"from the settlement by the stone"
"arrow maker"
"of the Caspian Sea"
"rock, stone"
"dark, dark-haired"
"third-born or third generation"
"greatest of the Aemilians"
"wise protector"
"dealer in provisions and supplies"
"joy, happiness"
"short form of Wesley or Weston"
"watchful, vigilant (via Casey influence)"
"measure, measurement tool"
"western enclosure"
"one who catches fish"
Similar sound: These names share phonetic patterns with Flynn — 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 Flynn.
Rhythm: Flynn is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.