Siar sits next to 4 phonetic neighbors — Sheer, Ciar, and Seer are the closest matches by sound. Most share Siar's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"westward, to the west"
"son of Roderick"
"son of the gray-haired one"
"Gaelic diminutive form of Ferdinand"
"from the southern lands"
"from the fort (place name origin)"
"little red one"
"from Renton, town name"
"resembling the bright one"
"claw, swift predator (via Talon)"
"fair warrior, fair hero"
"dark-haired chieftain"
"guardian of riches"
"salmon"
"gentle birth, beloved"
"sharp, intelligent"
"resolute protector, determined guardian"
"raven"
Similar sound: These names share phonetic patterns with Siar — 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 Siar.
Rhythm: Siar is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.