Indigo sits next to 4 phonetic neighbors — Indiana, Indira, and Indy 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
"deep blue-purple color, from India"
"bright fame, shining fame"
"pure, holy, chaste"
"modern melodic invention"
"the great sea, vast waters"
"party, folk gathering with music"
"little red one"
"dark one, descendant of the dark one"
"blood red, vibrant red"
"night"
"high, noble (Ali) + grace (Anna)"
"child of heaven"
"bee"
"short form of Penelope"
"God is gracious"
"to warn, admonish"
"born on Christmas Day"
"pet form of Sarah"
"of the crooked hill"
"glowing ember, burning coal remnant"
"fragrant spice"
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 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.