Adan sits next to 4 phonetic neighbors — Eden, Aidan, and Adena are the closest matches by sound. Most share Adan's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"earth, ground"
"lake, waterfall"
"beloved, dear one"
"eternal, everlasting"
"talented; refined"
"noble, exalted"
"beloved, wished-for child"
"Likely a creative variant of Danielle, meaning God is my judge"
"defender of mankind"
"land of the Bretons, from Brittany France"
"blend of Marley (pleasant meadow) and Lena (light, torch)"
"variant of Chloris, flower goddess"
Similar sound: These names share phonetic patterns with Adan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hebrew origins, giving them the same cultural heritage as Adan.
Rhythm: Adan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.