Theo sits next to 3 phonetic neighbors — Leo, Teo, and Theo are the closest matches by sound. Most share Theo's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"gift of God"
"light, illumination"
"bright fame"
"cloth walker, one who treads cloth"
"one who saws wood"
"keeper of the game preserve"
"universal, whole"
"God will uplift, exalt"
"earth (in Arabic, adama)"
"little fire"
"son of Jack"
"gracious, dear, beloved"
"heavenly being, celestial guardian"
"from Hadria, of the Adriatic"
"broom-covered hill"
"fortified hill"
"master, conqueror"
"western farmstead, western settlement"
"cheerful settlement"
Similar sound: These names share phonetic patterns with Theo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek (theodoros) origins, giving them the same cultural heritage as Theo.
Rhythm: Theo is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.