Cosmo sits next to 4 phonetic neighbors — Cosimo, Cosmos, and Roscoe are the closest matches by sound. Most share Cosmo's Italian-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"order, universe"
"noble and ready"
"light hill (from city name)"
"linden tree hill"
"huckleberry berry plant"
"of the sea, of the lake"
"lion-hearted, brave"
"set apart, destined"
"follower of Dionysos, of Zeus"
"little fire (from Irish aodh)"
"people's lord"
"marsh dweller"
"place of alder trees"
"flowing water, river"
"ruler of the world"
"primordial force of attraction"
"variant of Pruitt, meaning valiant"
"father of God"
"man from South Munster (south Munster province)"
"word name from archery term"
Similar sound: These names share phonetic patterns with Cosmo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Cosmo.
Rhythm: Cosmo is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.