Tristian sits next to 4 phonetic neighbors — Tristan, Tristin, and Tristen are the closest matches by sound. Most share Tristian's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"noise, tumult"
"follower of Dionysus, god of wine"
"huckleberry berry plant"
"elf ruler"
"modern invented name, valley dweller (from -den suffix)"
"son of the south"
"rock worker, craftsman"
"noble lord, feudal warrior"
"hard spear (from Welsh Peredur)"
"lime tree hill"
"of the sea (possible etymology)"
"from Airelle (a place in Normandy, France)"
"father of peace"
"God is gracious"
"servant of God"
"spear, acquired"
"mill town, settlement by the mill"
"one who observes, explorer"
"row of trees by the wood"
"crooked nose; bent river"
"red-haired, little redhead"
Similar sound: These names share phonetic patterns with Tristian — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Pictish/Celtic origins, giving them the same cultural heritage as Tristian.
Rhythm: Tristian is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.