Londyn sits next to 4 phonetic neighbors — London, Landon, and Lyndon are the closest matches by sound. Most share Londyn's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"from Londinium, fort on the Thames"
"home ruler"
"white hawk or modern creation"
"those who are allied"
"breeze, air current"
"spear rule, lord of the spear (via Gerald)"
"all-powerful"
"a million (aspirational wealth, abundance)"
"wise, all-knowing"
"place of the blue dye plant"
"strong lord"
"army, nobleman"
"renowned in the land"
"warrior, slayer"
"phonetic variant of Ryker"
"the Christ, savior figure"
"exalted, Roman"
"the void, primordial emptiness"
"twin"
"title of honor (from Titus)"
"Eorla's settlement (personal name etymology)"
Similar sound: These names share phonetic patterns with Londyn — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Celtic/Latin origins, giving them the same cultural heritage as Londyn.
Rhythm: Londyn is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.