Fiesta sits next to 3 phonetic neighbors — Siesta, Frieda, and Greta are the closest matches by sound. Most share Fiesta's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"festival, celebration, feast"
"honorific of Saint Jeanne de Chantal"
"Joining; concord; agreement - from Greek harmonia, the goddess of h..."
"little dark one, dark-haired"
"sweet, diligent (from bee symbolism)"
"mother"
"delicate sheer fabric"
"variant of Toya meaning victory; toi means you in French"
"Mary: beloved, wished-for child (Hebrew); Kathryn: pure, clear (Greek)"
Similar sound: These names share phonetic patterns with Fiesta — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Spanish origins, giving them the same cultural heritage as Fiesta.
Rhythm: Fiesta is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.