Jackson sits next to 4 phonetic neighbors — Jaxon, Mason, and Hudson are the closest matches by sound. Most share Jackson's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Jack"
"resolute protector, strong-willed guardian"
"the Lord saves"
"From the Hebrew 'Yitzhak'; the biblical patriarch Isaac was the son..."
"valley dweller"
"strong, firm, enduring"
"will-helmet, resolute protector"
"lion"
"little fire"
"park keeper"
"From the Scottish place name Logan; a topographic name from Gaelic ..."
"gift of God"
"powerful, brave king"
"son of Brice"
"father of peace"
"wealthy"
"father of many nations"
"unbranded cattle, one who stands alone"
"ascended, exalted"
"From the Aramaic 'Toma', meaning twin; borne by the Apostle Thomas"
Similar sound: These names share phonetic patterns with Jackson — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have English patronymic surname origins, giving them the same cultural heritage as Jackson.
Rhythm: Jackson is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.