Rostam sits next to 3 phonetic neighbors — Rustam, Roshan, and Reza are the closest matches by sound. Most share Rostam's Persian-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"strong, heroic warrior"
"royal warrior, brave king"
"daring, bold"
"honorable (title of respect)"
"intimate, sociable"
"celebration of birth"
"firm, strong, steadfast"
"moisture that quenches thirst"
"king, royal"
"harbor, port"
"God's inspiration"
"Canopus star, bright star"
"light of Muhammad"
"from Sebaste (via Sebastian)"
"keeper of treasure"
"Blessing, divine favor"
Similar sound: These names share phonetic patterns with Rostam — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Persian/Avestan origins, giving them the same cultural heritage as Rostam.
Rhythm: Rostam is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.