Frederick sits next to 4 phonetic neighbors — Friedrich, Fredrik, and Federico are the closest matches by sound. Most share Frederick's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"peaceful ruler"
"one who is learned"
"lover of churches"
"strength, manly beauty"
"from the green valley"
"strong and healthy"
"son of Lawrence"
"thunder god"
"son of Jens (son of John)"
"hunter, one who hunts"
"the Lord is my God"
"tumult, noise"
"wisdom, good sense"
"dear one of God"
"little saint"
"lotus flower"
"lives near reeds"
"God has consoled"
"best"
"victory of the people (from Nicholas)"
"severe, strict"
Similar sound: These names share phonetic patterns with Frederick — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Frederick.
Rhythm: Frederick is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.