Caysen sits next to 5 phonetic neighbors — Kaysen, Mason, and Jason are the closest matches by sound. Most share Caysen's Old English/American-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Case; from the marsh"
"Harry's son, son of the ruler"
"king, ruler"
"wise, judicious"
"modern invented name, possibly 'sincere air' or 'great river'"
"luminous, shining"
"remembered by God"
"valley dweller, from the valley"
"son of Peter (son of the rock)"
"thankful, grateful"
"shelter, sanctuary"
"earth"
"my messenger, my angel"
"from the western direction"
"God is with us"
"worker in steel (occupational surname)"
"mighty peace"
"stone worker (via Mason)"
"diminutive of Scott"
"winding river"
Similar sound: These names share phonetic patterns with Caysen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English/American origins, giving them the same cultural heritage as Caysen.
Rhythm: Caysen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.