Reginald sits next to 4 phonetic neighbors — Ronald, Renald, and Reynold are the closest matches by sound. Most share Reginald's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"counsel, power"
"spiritually reborn through baptism"
"sea"
"ancient, enduring"
"red river settlement"
"Harry's son, son of the ruler"
"God is gracious"
"village of the cross, farm by the cross"
"wealthy guardian"
"faithful, loyal, trustworthy"
"strong as a lion"
"from the western direction"
"associated with luxury and elegance"
"elf warrior"
"descendant of Braonán, tearful one"
"modern invented name, possibly 'noble leader'"
"strong, virtuous, honorable"
"strength"
"high stronghold, fort on the headland"
"son of Case; from the marsh"
"the koa (warrior tree)"
Similar sound: These names share phonetic patterns with Reginald — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Reginald.
Rhythm: Reginald is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.