Callum sits next to 4 phonetic neighbors — Calum, Calvin, and Colm are the closest matches by sound. Most share Callum's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"dove"
"beloved, darling"
"son of Elias"
"priceless one, of inestimable worth"
"descendant of the little king"
"son of Carsun, dweller near the marsh"
"cart driver, transporter of goods"
"courageous, valiant"
"fine, lovely"
"rowan tree (red-berried tree)"
"son of James"
"from the valley of water"
"Yahweh is gracious"
"my God is the Lord"
"descendant of Bradán (salmon)"
"from the wetlands"
"Little hollow; from the little hollow place"
"rich protector"
"elm grove"
Similar sound: These names share phonetic patterns with Callum — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin via Scottish Gaelic origins, giving them the same cultural heritage as Callum.
Rhythm: Callum is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.