Alan sits next to 4 phonetic neighbors — Allen, Allan, and Aaron are the closest matches by sound. Most share Alan's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"handsome"
"the river Jordan"
"gift of God"
"God is gracious (via Jack, from John)"
"feller of trees, hewer"
"man from Lucania"
"high mountain"
"soldier"
"from the eastern homestead"
"glorious, famous"
"son of the sea"
"Twin"
"the new house"
"young seal, seal-born"
"from the hollow"
"full of goodness"
"jet black; speed"
"broom-covered hill"
"small, humble"
"dark one, black"
"ruler of the people"
Similar sound: These names share phonetic patterns with Alan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Celtic origins, giving them the same cultural heritage as Alan.
Rhythm: Alan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.