Sumner sits next to 5 phonetic neighbors — Summer, Spencer, and Gunner are the closest matches by sound. Most share Sumner's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"summoner, one who calls forth"
"claw, swift predator (via Talon)"
"little one, shapely"
"royal power"
"healer, one who heals"
"strength, authority, force"
"symbol of wisdom and knowledge"
"warrior, military companion"
"appointed by God"
"playful one"
"one who mows or cuts"
"the new house"
"sharp, intelligent"
"invented modern name"
"wealthy protector"
"raven sword, renowned with the blade"
"supplanter, held by the heel (via Jake/Jacob)"
"settlement on the River Ren"
"from the southern lands"
"son of Alexander (defender of men)"
Similar sound: These names share phonetic patterns with Sumner — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French origins, giving them the same cultural heritage as Sumner.
Rhythm: Sumner is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.