Jo sits next to 4 phonetic neighbors — Joe, Zo, and Bo are the closest matches by sound. Most share Jo's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"God will add, God will increase"
"heaven, the afterlife realm of joy"
"ash tree meadow"
"Finnish feminine name, possibly related to air or era"
"torch, sun ray"
"Odin's warrior"
"beloved eye (Hawaiian elements)"
"purity, cleanliness"
"precious green stone"
"briar rose (fairy tale association)"
"hardworking, industrious (via Millicent)"
"gracious, favored"
"unlucky, ill-omened"
"uproar, disturbance"
"healing herb, health"
"hill"
"remarkable story, myth"
"creative American formation, possibly from Tatiana (arranger)"
"bright grace of God"
"lime tree meadow"
"anointed one (via Christos)"
Similar sound: These names share phonetic patterns with Jo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hebrew origins, giving them the same cultural heritage as Jo.
Rhythm: Jo is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.