Nikolai sits next to 4 phonetic neighbors — Nicholas, Nicola, and Mikael are the closest matches by sound. Most share Nikolai's Russian-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"victory of the people"
"master of inspired frenzy"
"best"
"dove"
"fallow land, uncultivated land"
"always king"
"son of Karr"
"brave warrior (later folk etymology)"
"mind, spirit, heart"
"helper, one who helps"
"great"
"downy-bearded, youth"
"to live, to dwell"
"warrior lion"
"victory of the people"
"vigorous, flourishing"
Similar sound: These names share phonetic patterns with Nikolai — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek (Nikolaos) origins, giving them the same cultural heritage as Nikolai.
Rhythm: Nikolai is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.