Birger sits next to 5 phonetic neighbors — Burger, Bergen, and Bjorn are the closest matches by sound. Most share Birger's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"to help, to save, to rescue"
"happy, fortunate, blessed"
"God is gracious"
"work and power"
"prosperous, equal in rank"
"growing, increasing, flourishing"
"sacred mountain"
"bear"
"brilliant helper"
"light (from Lucius)"
"praised, praiseworthy"
"Bright light, torch, shining one"
"Valley of the linden trees"
"gold, golden one"
"dweller at the wood"
Similar sound: These names share phonetic patterns with Birger — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Norse bjarga origins, giving them the same cultural heritage as Birger.
Rhythm: Birger is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.