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"
"cushion, pillow"
"bright lake, shining pool"
"pure"
"luminous, brilliant"
"alert, observant"
"hollow, cauldron"
"prince or chieftain's daughter"
"slender, graceful"
"of the crooked hill"
"curly-haired, descendant of Caiside"
"pearl"
"hawk-like (possible alternative)"
"little star (possible etymology)"
"sacred, inviolate"
"garden of holly"
"wise, knowledgeable"
"pearl"
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.