Theodorus sits next to 4 phonetic neighbors — Theodore, Theodoric, and Theodosius are the closest matches by sound. Most share Theodorus's Greek-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"gift of God"
"short form of Reinhard (pure heart) or Reinier"
"all-holy, entirely sacred"
"California (place name nickname)"
"Athenian, of Attic culture"
"one who carries the treasure"
"royal, kingly"
"Red-haired"
"forest ranger, game warden"
"superior, of the highest quality"
"gift of healing"
"small, little"
"variant of Elias: my God is Yahweh"
"treasurer, keeper of treasure"
"from Nazareth, consecrated to God"
"lord, master"
"grace, kindness"
"keeper of treasure"
Similar sound: These names share phonetic patterns with Theodorus — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Ancient Greek origins, giving them the same cultural heritage as Theodorus.
Rhythm: Theodorus is a 4-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.