Glender sits next to 4 phonetic neighbors — Glenda, Glennie, and Gender are the closest matches by sound. Most share Glender's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"valley, mountain glen"
"shield-wolf, defender"
"lake, pool"
"little Jon, feminine form of Jon"
"elf counsel (via Alfrid)"
"God will increase; from a wooded valley"
"little red one; graceful river"
"Christ-carrier"
"free woman"
"lady, mistress of the house"
"lily, rose"
"Beautiful; fair one"
"Reborn; born again; variant of Renee"
"Variant of Joan/Joanne, from Hebrew Yohanan meaning God is gracious..."
"noble, patrician"
"Pure; stream"
"little joy, dear song"
Similar sound: These names share phonetic patterns with Glender — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scottish Gaelic origins, giving them the same cultural heritage as Glender.
Rhythm: Glender is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.