Niall sits next to 4 phonetic neighbors — Neil, Neal, and Nils are the closest matches by sound. Most share Niall's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"champion"
"from the town, settlement"
"little fire"
"god spear"
"son of Peter (son of the rock)"
"broad valley"
"from Leicester"
"son of Rand, son of the shield-wolf"
"new house"
"red-haired, little redhead"
"God has remembered"
"linden tree, lime tree"
"helpful person"
"fortress, walled Roman camp"
"to conquer, to win"
"word name from archery term"
"elf ruler"
"son of Adam"
"elm grove"
"peaceful ruler"
"victory of the people"
Similar sound: These names share phonetic patterns with Niall — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Irish origins, giving them the same cultural heritage as Niall.
Rhythm: Niall is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.