Andy sits next to 4 phonetic neighbors — Andie, Randy, and Sandy are the closest matches by sound. Most share Andy's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"manly, brave"
"requested of God"
"servant of God"
"powerful leader of the folk"
"God will strengthen"
"befitting a king"
"illustrious through nobility"
"little star"
"to tame, to subdue"
"free man, freeholder of land"
"healer (via Jason/Iason)"
"one who crafts arrows"
"light"
"rest, repose"
"growth, abundance"
"divine power (from Oswald)"
"statement of belief, system of faith"
"helper, one who helps"
"son of Andrew (manly)"
"firebrand"
Similar sound: These names share phonetic patterns with Andy — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Andy.
Rhythm: Andy is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.