Ffion sits next to 3 phonetic neighbors — Fiona, Fionn, and Fee-on are the closest matches by sound. Most share Ffion's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"foxglove flower"
"shining, sparkling, full of light"
"grace, favor"
"royal secretary, official"
"kiss"
"sovereignty, rule"
"moonlight, shining light"
"Pledged to God; my God is an oath"
"opening, unfolding"
"dear friend, beloved companion"
"great house"
"exalted, heavenly"
"good person, calm"
"earth mother, primordial goddess"
Similar sound: These names share phonetic patterns with Ffion — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh origins, giving them the same cultural heritage as Ffion.
Rhythm: Ffion is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.