Leo sits next to 3 phonetic neighbors — Leon, Theo, and Lio are the closest matches by sound. Most share Leo's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"lion-hearted, brave"
"rival, eager to excel"
"supplanter"
"forest, woods"
"soldier"
"he who carries the heavens"
"soldier, warrior"
"God is salvation, the Lord saves"
"olive tree"
"of uncertain origin, possibly barberry hill"
"son of Madoc"
"friend, darling"
"Stone worker; one who builds with stone"
"God is gracious"
"thankful one"
"advice, counsel"
"farmer, earthworker"
"mild, peaceful"
Similar sound: These names share phonetic patterns with Leo — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Leo.
Rhythm: Leo is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.