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"
"eternal, everlasting"
"beloved, wished-for child"
"land of the Bretons, from Brittany France"
"blend of Marley (pleasant meadow) and Lena (light, torch)"
"lake, waterfall"
"defender of mankind"
"talented; refined"
"variant of Chloris, flower goddess"
"salt lake"
"variant of Siobhan (God is gracious)"
"Likely a creative variant of Danielle, meaning God is my judge"
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.