Tennyson sits next to 4 phonetic neighbors — Henderson, Benson, and Lennox are the closest matches by sound. Most share Tennyson's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Dennis"
"pool near the elm tree"
"dweller near ash trees"
"from the rocky hill, crag dweller"
"forest, wood, timber"
"new town"
"priceless, flourishing (via Anthony/Antonius)"
"little fire"
"powerful giant, cosmic force"
"tube, channel"
"God is my salvation"
"son of Kai/Kay (from Scandinavian -sen suffix)"
"pleasant stream"
"rejoice, be glad (via Gaius/Caio)"
"elevated, sublime, lofty"
"place of the Koniag people"
"little Hugh, small-hearted one"
"island meadow"
"victory of the people"
Similar sound: These names share phonetic patterns with Tennyson — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have English origins, giving them the same cultural heritage as Tennyson.
Rhythm: Tennyson is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.