Negan sits next to 3 phonetic neighbors — Megan, Regan, and Logan are the closest matches by sound. Most share Negan's American-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"invented modern name, no established meaning"
"thankful warrior"
"slender, narrow"
"young warrior"
"bear strength"
"broad clearing, wide meadow"
"the twin stars (Castor and Pollux)"
"victory of the people"
"color, vibrant shine"
"dark red, crimson"
"lord, respected elder (if from Sire)"
"ancient, enduring"
"son of David"
"strong lord, fierce chief"
"Yahweh has heard"
"gracious gift"
"ruler of the people"
"firebrand, son of Tye"
"farmer, cultivator, tenant farmer"
"having supreme power"
"dweller by the lime trees"
Similar sound: These names share phonetic patterns with Negan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have American origins, giving them the same cultural heritage as Negan.
Rhythm: Negan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.