Mattie sits next to 4 phonetic neighbors — Maddie, Millie, and Hattie are the closest matches by sound. Most share Mattie's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"gift of God"
"the most beautiful one"
"princess, noblewoman"
"pearl"
"Mae (spring month) + Lynn (lake)"
"God is gracious"
"to give thanks, thankfulness"
"jovial, cheerful, good-humored"
"cassia tree, cinnamon spice"
"universal, entire"
"high, exalted, rising"
"Yahweh is merciful"
"hillside meadow"
"defender of men"
"dear to Saturn"
"spiritually renewed"
"entirely beautiful"
"Yahweh is God"
"bearer of Christ (from Christopher)"
"beautiful jade, delicate"
"free man, free woman"
Similar sound: These names share phonetic patterns with Mattie — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hebrew (Matthew root) origins, giving them the same cultural heritage as Mattie.
Rhythm: Mattie is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.