Kai sits next to 4 phonetic neighbors — Kay, Kye, and Ky are the closest matches by sound. Most share Kai's Hawaiian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"sea, ocean"
"star of the sea"
"sword, blade"
"moon, moonlike"
"earth, soil"
"son of Maud"
"glowing ember, smoldering fire"
"violet flower"
"from the marshy ground"
"defender of men"
"noble father's daughter"
"pure, holy, chaste"
"defender of men"
"pet form of Sarah"
"little one (diminutive suffix)"
"elder tree island"
"pet form of Mary"
"Mae (spring month) + Lynn (lake)"
"pure world beauty"
"entirely beautiful"
"blue jay bird plus meadow"
Similar sound: These names share phonetic patterns with Kai — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hawaiian origins, giving them the same cultural heritage as Kai.
Rhythm: Kai is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.