Mckay sits next to 3 phonetic neighbors — McKae, Mackay, and MacKay are the closest matches by sound. Most share Mckay's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"Son of Aodh (fire god)"
"long-lasting"
"Peace"
"creative American invention with La- prefix"
"people, nation (from Tamika root)"
"noble one from the valley"
"God is gracious, beautiful lake"
"modern invented name"
"Night; dark beauty"
"people of the forest"
"something secret or unknown, a religious secret rite"
Similar sound: These names share phonetic patterns with Mckay — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scottish Gaelic origins, giving them the same cultural heritage as Mckay.
Rhythm: Mckay is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.