Royce sits next to 4 phonetic neighbors — Boyce, Roy, and Bryce are the closest matches by sound. Most share Royce's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of the king"
"southern settlement, south farm"
"victory of the people (from Nicholas)"
"great town"
"opportunity, happenstance"
"may God protect"
"king, royalty"
"son of the blessed one"
"resolute protector's son"
"helper, one who helps"
"of the Julian clan, youthful"
"to rejoice, joyful"
"battle"
"spear of God (from Oscar)"
"altar/hearth of God"
"from the people (damos)"
"native Hawaiian hardwood tree"
"steadfast, firm"
"peace power"
"lucky, perfect"
Similar sound: These names share phonetic patterns with Royce — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French via English origins, giving them the same cultural heritage as Royce.
Rhythm: Royce is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.