Demarco sits next to 4 phonetic neighbors — Marco, Demario, and Marcus are the closest matches by sound. Most share Demarco's Italian/Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"of Mark, belonging to Mars"
"God is my help"
"paw, claw"
"from the heathland"
"creative American original"
"uncertain; possibly Romani personal name with regional meaning"
"champion, winner"
"chip off the old block"
"growth, abundance, increase"
"resilient fabric, American spirit"
"maturity, moral soundness"
"little rock"
"modern invented name"
"farm on a hill, settlement by a mound"
"victory of the people (as short form of Nicholas)"
"power of the people"
"to care for, to cherish"
"dog (loyal companion)"
"he who holds firm the good"
"reborn, renewed"
"town in the forest (alternate etymology)"
Similar sound: These names share phonetic patterns with Demarco — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Italian/Latin origins, giving them the same cultural heritage as Demarco.
Rhythm: Demarco is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.