Sender sits next to 3 phonetic neighbors — Sander, Alexander, and Zander are the closest matches by sound. Most share Sender's Greek via Yiddish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"defender of men"
"vitality, living"
"gift, wealthy"
"seventh letter"
"father is a lamp/candle"
"dove (from Yona/Jonah)"
"Cathay, the Middle Kingdom"
"spring of water, water gift"
"gift of God (gift of Yahweh)"
"proclaimer of peace"
"boundless, infinite, immeasurable"
"faithful as a dog"
"beloved, good"
"divine gift, blessing from God"
Similar sound: These names share phonetic patterns with Sender — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek via Yiddish origins, giving them the same cultural heritage as Sender.
Rhythm: Sender is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.