Alistair sits next to 4 phonetic neighbors — Alexander, Alastair, and Alasdair are the closest matches by sound. Most share Alistair's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"defender of men"
"wealthy guardian"
"dweller near the heath"
"noble lord"
"the color gray, from the gray lands"
"he who holds firm the good"
"from the marshy plain"
"God will add, God will increase"
"admirable, worthy"
"city of God (alternate interpretation)"
"wealthy guardian, guardian of fortune"
"may God protect, holder of the heel"
"narrow water"
"rock, harmony"
"muddy place, ditch"
"valley, hollow"
"his excellence, his preeminence"
"crooked mouth, wry-mouthed"
Similar sound: These names share phonetic patterns with Alistair — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Alistair.
Rhythm: Alistair is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.