Indigo sits next to 3 phonetic neighbors — Indio, Iggy, and Diego are the closest matches by sound. Most share Indigo's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"blue-purple dye, the color indigo"
"thunder ruler, powerful"
"brown, chief"
"impulsive, little king"
"Greece, Ionia (biblical Javan)"
"variant of Lakin: small play, sport"
"may God protect"
"bald, little bald one"
"sun, sunshine"
"warrior's estate"
"from the Welsh Seisyll"
"lord of the marches, borderlord"
"occupational surname for cellar manager"
"a large inland body of water"
"tailor, cutter of cloth"
"ruler of the people"
"ruler of supernatural beings"
"powerful (alternative interpretation)"
"greatest stream (via Maxwell)"
"wolf"
"variant of Caleb, meaning faithful"
Similar sound: These names share phonetic patterns with Indigo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek via Latin origins, giving them the same cultural heritage as Indigo.
Rhythm: Indigo is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.