Sheldon sits next to 3 phonetic neighbors — Shelton, Weldon, and Eldon are the closest matches by sound. Most share Sheldon's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"steep valley settlement"
"rocky cliff, crag"
"counselor, advisor"
"fortunate, blessed"
"eternal"
"green/fresh river"
"brave people, bold folk"
"boar-friend, warrior companion"
"settlement of a sword-bearer"
"joy, happiness"
"God is my strength"
"warrior, strong fighter"
"son of the prosperous protector"
"nobleman, warrior"
"fisherman"
"God's salvation"
"son of Ellis"
"generous, tolerant"
"steep hill meadow"
"lion"
"royal settlement, king's town"
Similar sound: These names share phonetic patterns with Sheldon — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Sheldon.
Rhythm: Sheldon is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.