Luis sits next to 3 phonetic neighbors — Lewis, Louis, and Lucas are the closest matches by sound. Most share Luis's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"famous warrior"
"light"
"gift of God"
"flourishing, long-lived"
"Saint James"
"gift of God"
"God is salvation, YHWH saves"
"from Lucania"
"From Hebrew 'Gavriel'; the archangel Gabriel appears in the Bible, ..."
"strong as a lion"
"follower of Christ"
"my God is Yahweh"
"powerful, brave king"
"From the Aramaic 'Toma', meaning twin; borne by the Apostle Thomas"
"steadfast, firm"
"master, conqueror"
"Free"
"God judges"
"man, full-grown man"
"God is gracious"
Similar sound: These names share phonetic patterns with Luis — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Luis.
Rhythm: Luis is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.