Haslyn sits next to 4 phonetic neighbors — Hazel, Jaslyn, and Katelyn are the closest matches by sound. Most share Haslyn's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"hazel grove by the pool"
"noble, of noble kind"
"modern coinage, melodic invention"
"of Maria, of Mary"
"Bright one of the meadow; combination of Lena (light, bright) and L..."
"black meadow clearing"
Similar sound: These names share phonetic patterns with Haslyn — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Modern English compound origins, giving them the same cultural heritage as Haslyn.
Rhythm: Haslyn is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.