Garrison sits next to 4 phonetic neighbors — Harrison, Garrison, and Garson are the closest matches by sound. Most share Garrison's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Garret, son of the spear bearer"
"little rock"
"farmer, estate steward"
"grace, blessing"
"son of Rand, son of the shield-wolf"
"from Galloway"
"marsh dweller"
"follower of Dionysos, of Zeus"
"from the surname of poet W.H. Auden"
"safe, unharmed (proposed etymology)"
"supplanter, may God protect"
"man from the mountain"
"boar-friend, warrior companion"
"modern invented name, unique spirit"
"held by the heel"
"peace of the father"
"order, universe"
"God is gracious and humble"
"rival, eager to emulate"
"son of Thomas, son of the twin"
Similar sound: These names share phonetic patterns with Garrison — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic/English origins, giving them the same cultural heritage as Garrison.
Rhythm: Garrison is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.