Kessler sits next to 4 phonetic neighbors — Westly, Kestler, and Kesler are the closest matches by sound. Most share Kessler's German-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"copper merchant, kettlemaker"
"uncertain — possibly related to the island of Ikaria"
"elder tree island"
"supplanter, one who takes another's place"
"hollow, vain (from Latin Cassius)"
"village of the Danes"
"young warrior"
"brave as a bear, bold bear"
"son of God-peace"
"champion, cloud"
"at the barns, near the granary"
"gift"
"weaver"
"God is gracious"
"fingernail, claw"
"mountain, elevated"
"God has heard (from Ja-/Jacob root) + spirit of battle (from Kayden)"
"appointed by God"
"of the Jordan River"
"firebrand, bold warrior"
"handsome at birth"
Similar sound: These names share phonetic patterns with Kessler — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Middle High German origins, giving them the same cultural heritage as Kessler.
Rhythm: Kessler is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.