Halo sits next to 4 phonetic neighbors — Haley, Milo, and Cleo are the closest matches by sound. Most share Halo's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"ring of light"
"life, living"
"moon"
"Jerusalem (poetic)"
"fair and smooth"
"fortress on the river (possible Celtic root)"
"renown, honor"
"ugly-headed (original Gaelic)"
"fair, comely"
"oarsman, rower"
"father rejoices"
"beloved, wished-for child (from Hebrew Miriam via Mary)"
"grace, favor"
"flourishing, prosperous"
"purity, grace"
"heavenly, of the sky"
"precious gem"
"clean, unsullied"
"a day's travel (original etymology)"
"star, heavenly body"
Similar sound: These names share phonetic patterns with Halo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Halo.
Rhythm: Halo is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.