Duke sits next to 4 phonetic neighbors — Luke, Huck, and Buck are the closest matches by sound. Most share Duke's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"leader, military commander"
"battle, warrior spirit"
"carried by God"
"lion hardy"
"son of the red-haired one"
"he who holds firm the good"
"son of Brice"
"elder, more important"
"young lion"
"great town"
"pure, without blemish"
"lucky, perfect"
"work and power combined"
"large gun, artillery piece"
"divinely selected (spiritual connotation)"
"son of Egan, little fire"
"beloved"
"horse friend"
"descendant of Madan (little dog)"
"arrow maker"
"wood, forest"
Similar sound: These names share phonetic patterns with Duke — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Duke.
Rhythm: Duke is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.