Eternity sits next to 4 phonetic neighbors — Serenity, Destiny, and Felicity are the closest matches by sound. Most share Eternity's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"infinite time, endless existence"
"free one, Frenchman"
"water"
"eternal flower, forever flowering"
"beautiful, fine, delicate"
"bright, radiant (from Slavic root)"
"star"
"little Goth, from the Germanic tribe"
"grace, favor"
"hawk-like"
"from the forest, woodland"
"raven, dark-haired one"
"from the wilderness of thorns"
"navigator, of the navy"
"counsel power"
"meadow near the church"
"God is gracious"
"little one who is loved"
"brave, vigilant"
"pretty, beautiful"
"joyful"
Similar sound: These names share phonetic patterns with Eternity — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Eternity.
Rhythm: Eternity is a 4-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.