Derek sits next to 3 phonetic neighbors — Derrick, Eric, and Darrick are the closest matches by sound. Most share Derek's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"ruler of the people"
"crooked river, winding stream"
"divine healer"
"passion, fire"
"the healer (Iason)"
"traverser, one who crosses"
"long-lived, perennial stream"
"beloved son"
"between two hills"
"descendant of Grádaigh"
"follower of Christ; anointed one"
"invented name, possibly evoking sky"
"divine messenger, heavenly being"
"narrow road, path"
"dispenser of provisions, household steward"
"Lord, have mercy (liturgical)"
"God is willing"
"Finnish person, Norseman"
"free man"
"favored by the gods"
"to prevail, to win"
Similar sound: These names share phonetic patterns with Derek — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Derek.
Rhythm: Derek is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.