Kaysen sits next to 5 phonetic neighbors — Jason, Mason, and Grayson are the closest matches by sound. Most share Kaysen's American English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"modern American creation"
"king"
"group, band, team"
"honest, steadfast"
"hollow, ravine"
"battle strength"
"from the green valley"
"brave in battle"
"great chief, eminent lord"
"passion, fire"
"lives near a bridge"
"rest (via Rocco)"
"healer (via Jason)"
"home ruler"
"water, thermal waters (place name)"
"from Reims"
"scholar"
"from the island of Rhodes"
"narrow strait, channel"
"sovereign, owner"
"candle maker or seller"
Similar sound: These names share phonetic patterns with Kaysen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have American English origins, giving them the same cultural heritage as Kaysen.
Rhythm: Kaysen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.