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"
"son of Jack"
"mind, intellect, spirit"
"sea, ocean (kai component)"
"God supports, Yahweh supports"
"one who brings news"
"God's darling"
"herb farm, meadow settlement"
"wild goat (ibex)"
"renowned warrior"
"Thor's stone"
"wholehearted (short for Caleb from Hebrew)"
"lasting impact, heritage"
"good man, strong man"
"God is salvation"
"strong, virtuous, honorable"
"God sees, God is my strength"
"God is gracious"
"wild rose bush"
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.