Coulter sits next to 4 phonetic neighbors — Colter, Colt, and Coulter are the closest matches by sound. Most share Coulter's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"knife, cutting blade of a plow"
"delight, paradise (as in Eden)"
"son of Matthew"
"free spirit, nonconformist"
"farmer, peasant landholder"
"my flock belongs to God"
"son of Myer/Meyer"
"fortune, chance"
"strife, contest"
"one who heals"
"cross"
"lion"
"servant of a noble, warrior retainer"
"American variant of Dante"
"father of multitudes"
"bold, brave"
"that which one believes"
"baker"
"of Sean"
"diminutive of Hugh (heart, mind)"
Similar sound: These names share phonetic patterns with Coulter — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English/Latin origins, giving them the same cultural heritage as Coulter.
Rhythm: Coulter is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.