Wilbur sits next to 4 phonetic neighbors — Gilbert, Wilber, and Walter are the closest matches by sound. Most share Wilbur's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"resolute fortress, determined will"
"modern invented name; Ty (strength) + aire (air, atmosphere)"
"free man"
"bramble, thicket"
"great tide, sea flow"
"eagle land"
"God is gracious"
"short form of Matthew"
"dealer, trader"
"free man"
"deer, stag"
"dark, swarthy (from Irish Dubhán)"
"young person, noble youth"
"head, chief (as in penultimate)"
"island meadow, land near water"
"blooming, flourishing"
"flower sound"
"Akan people of Ghana"
"hill, marshland"
"lord, master (via Kyrie element)"
"winner, victorious fighter"
Similar sound: These names share phonetic patterns with Wilbur — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Wilbur.
Rhythm: Wilbur is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.