Eyner sits next to 5 phonetic neighbors — Einar, Axel, and Oskar are the closest matches by sound. Most share Eyner's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"one warrior, lone warrior"
"river, water course"
"place of destruction, the abyss"
"from the barley meadow (topographic)"
"moon, moonlight"
"Water of life; the distilled spirit drink"
"compassion of God"
"modern variant of Rudra with creative suffix"
"Settlement near a rift or cleft in the land; from Old English rif (..."
"pure, bright, shining"
"sensitive perceiver, artist of words"
"immortal, deathless"
"Inspired by the Japanese Kaizen philosophy meaning 'continuous impr..."
"a magical charm or spell; also a curse"
"prince"
"modern invented name combining elements of strength and wisdom"
Similar sound: These names share phonetic patterns with Eyner — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Norse origins, giving them the same cultural heritage as Eyner.
Rhythm: Eyner is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.