Tonya sits next to 4 phonetic neighbors — Tanya, Sonya, and Donna are the closest matches by sound. Most share Tonya's Russian-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"beyond praise, highly commendable"
"account; record of events"
"serene, calm, clear"
"goddess Savitri, divine solar figure"
"follower of Christ"
"fort on the Thames / from the Roman Londinium"
"grace, unfading"
"grace, favor"
"hospitable, welcoming to strangers"
"jealousy, covetousness"
"grace, God is my oath"
"place by the sea (possible Kumeyaay origin)"
"the ray of light"
"little honor, dear one"
"lord, master, lordly one"
"noble kind, of noble birth"
"of the sea, near the water"
"of Julius Caesar, July month"
"excessive pride in appearance"
"state of well-being"
"heavenly child, royal flowers"
Similar sound: These names share phonetic patterns with Tonya — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin Tatius family name origins, giving them the same cultural heritage as Tonya.
Rhythm: Tonya is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.