Britney sits next to 4 phonetic neighbors — Brittany, Britany, and Bethany are the closest matches by sound. Most share Britney's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"from Brittany, land of Britons"
"star, goddess of stars"
"exalted, sublime, high"
"song of joy"
"from the hay field"
"fair, righteous"
"youthful"
"joy, happiness"
"beautiful spirit"
"like a fairy"
"woman from Magdala, tower"
"heifer, young calf"
"God is gracious"
"joyful hill (from Wynn + hlaw)"
"burnt meadow"
"healer, one who makes whole"
"star"
"royal greatness, grandeur"
"of the meadow"
"mighty in battle"
"one who sails, seafarer"
Similar sound: These names share phonetic patterns with Britney — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have French/Latin origins, giving them the same cultural heritage as Britney.
Rhythm: Britney is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.