Seneca sits next to 3 phonetic neighbors — Senica, Sienna, and Sierra are the closest matches by sound. Most share Seneca's Native American cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"old stone place"
"sky, heavens, atmosphere"
"God is my judge"
"God is my light, flame of God"
"pearl"
"lake-bright (combined Welsh elements)"
"valiant; brave"
"gentle, maternal"
"priest"
"gift, abundance; place of peace"
"settlement of Kari's people"
"God is gracious"
"feminine given name"
"from the royal city"
"blue precious gemstone"
"noble and gentle"
"ugly head (archaic literal meaning)"
"ascending, uplifted by God"
"Mary (from Hebrew Miriam)"
"fortunate, favored by luck"
"eagle"
Similar sound: These names share phonetic patterns with Seneca — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Iroquoian origins, giving them the same cultural heritage as Seneca.
Rhythm: Seneca is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.