Tegan sits next to 3 phonetic neighbors — Teagan, Regan, and Keegan are the closest matches by sound. Most share Tegan's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"darling, treasured one"
"defender of men"
"modern invented variant of Taylor"
"swift warrior"
"bold, wild, fierce"
"noble, warrior, of high birth"
"cross, the cross of Christ"
"with melody, melodious"
"rye grain"
"son of Diot, follower of Dionysus"
"lake of the sage Kashyapa (Sanskrit etymology)"
"Greece/Ionian (Javan/biblical element)"
"initial-name, typically Andrew James or Anthony John"
"glowing, scorching"
"liberation, journey"
"lawman, legal authority"
"from Tyre, the ancient city"
"modern invented name in the -ayden tradition"
"honoring God"
"flat-topped hill settlement"
"descendant of the hound of valor"
Similar sound: These names share phonetic patterns with Tegan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh origins, giving them the same cultural heritage as Tegan.
Rhythm: Tegan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.