Alaster sits next to 4 phonetic neighbors — Alistair, Alastair, and Alexander are the closest matches by sound. Most share Alaster's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"defender of men, protector of mankind"
"ash tree"
"red-haired counselor"
"split, torn, broken apart"
"symbol of peace and wisdom"
"modern creative variant of Jason"
"visionary, seer"
"manly, masculine"
"gift of God"
"elaboration of Princeton, from Prince + ton"
"brave in battle, vigilant"
"holly corner, hazel grove"
"famous throughout the land"
"rich, wealthy"
"chance, good fortune"
"son of Daw (David), beloved son"
"one who sways, dancer"
"noble, famous"
"son of Madoc (gift of God)"
"God strengthens"
Similar sound: These names share phonetic patterns with Alaster — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek via Scottish Gaelic origins, giving them the same cultural heritage as Alaster.
Rhythm: Alaster is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.