Emrys sits next to 4 phonetic neighbors — Ambrose, Emery, and Emris are the closest matches by sound. Most share Emrys's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"immortal, not mortal"
"sea"
"oak grove, great"
"to rejoice, joyful"
"narrow water"
"Gomeric's mountain, power mountain"
"God is good"
"his excellence, his preeminence"
"dragon, serpent"
"little king"
"son of Harry"
"deep valley dwellers"
"dark warrior"
"lion, brave one"
"crowned with laurels, victorious"
"battle chieftain (Cerdic interpretation)"
Similar sound: These names share phonetic patterns with Emrys — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek via Welsh origins, giving them the same cultural heritage as Emrys.
Rhythm: Emrys is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.