Bert sits next to 4 phonetic neighbors — Burt, Bart, and Berta are the closest matches by sound. Most share Bert's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"bright, famous"
"star"
"flowing, moving freely"
"to soothe, to comfort"
"elf counsel"
"wonderful, to be admired"
"blooming, fresh, green"
"of the Claudian family"
"luminous, shining (via Lucinda)"
"from Lydia (ancient region of Asia Minor)"
"settlement of the Britons"
"battle horn"
"consecrated to God"
"numbness, the narcissus plant"
"meadow on a ledge"
Similar sound: These names share phonetic patterns with Bert — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Bert.
Rhythm: Bert is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.