Crux sits next to 4 phonetic neighbors — Knox, Brux, and Cruze are the closest matches by sound. Most share Crux's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"cross"
"vigilant in battle, watchful"
"occupational surname for a chapel keeper"
"fair, white, bright"
"water farmstead"
"lord of the earth, creation of the good earth"
"beloved strength"
"settlement on a hill"
"with great strength (via Arion)"
Similar sound: These names share phonetic patterns with Crux — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin crux origins, giving them the same cultural heritage as Crux.
Rhythm: Crux is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.