Saoirse sits next to 3 phonetic neighbors — Cersha, Sirsha, and Searsha are the closest matches by sound. Most share Saoirse's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"freedom, liberty"
"alert, observant"
"little dark one, dark-complexioned"
"strength in battle"
"pearl"
"curved hunting implement (boomerang-like)"
"descendant of Cathasach"
"dear, beloved, darling"
"little star (possible etymology)"
"from the hay field"
"white, bright, dawn"
"noble, high"
"wished-for child"
"descendant of Rian"
"little stream, flowing water"
"pure, holy, chaste"
"from Arcy (Norman French place name)"
"cushion, pillow"
"sunlight, moon (alternate etymology)"
Similar sound: These names share phonetic patterns with Saoirse — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish Gaelic origins, giving them the same cultural heritage as Saoirse.
Rhythm: Saoirse is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.