Will sits next to 4 phonetic neighbors — Bill, Phil, and Gil are the closest matches by sound. Most share Will's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"resolute protector"
"young male horse"
"house, home"
"yellow-haired, blonde"
"from the River Kelvin, narrow river"
"dedicated to Mars"
"land of the Bronck family"
"brotherly, genuine"
"crooked nose"
"strong, enduring"
"noble power, powerful ruler"
"the koa (warrior tree)"
"from the hollow"
"bold, riot"
"from the Adriatic region"
"lord (if related to Kyrie)"
"wealthy gift"
"of Mars, warlike"
"rye land; land where rye grows"
"dweller by the cliff ford"
Similar sound: These names share phonetic patterns with Will — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Will.
Rhythm: Will is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.