Rex sits next to 3 phonetic neighbors — Max, Tex, and Dex are the closest matches by sound. Most share Rex's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"king"
"ruler, sovereign (from Julius Caesar's name)"
"open, beginning"
"benevolent warrior"
"son of John (via Jack)"
"son of Brice"
"new"
"colt keeper, young horse handler"
"wolf"
"seven; divine completion"
"noble eagle (adal + aro)"
"God has given"
"continuous improvement (via Kaizen)"
"home power, ruler of work"
"river, great water (from Zaire)"
"son of Aodh (fire)"
"supplanter's son"
"to heal (from iasthai)"
"strength of God"
"high, noble"
"gift of the Lord"
Similar sound: These names share phonetic patterns with Rex — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Rex.
Rhythm: Rex is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.