Heydi sits next to 4 phonetic neighbors — Heidi, Haydi, and Sadie are the closest matches by sound. Most share Heydi's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"noble, of noble kind"
"from the volcanic land"
"God is gracious"
"palm tree (Jessenia genus)"
"of or from Nazareth"
"little rose"
"black, dark"
"queen"
"port, harbor"
"life, vitality (possible Arabic root)"
"stella (star)"
"God's gift"
"melodic blend with '-nelly' (meaning light or torch, from Norse)"
"grace"
"heavenly angel, sky angel"
"king of the underworld (Japanese mythology)"
"pure one"
"moon goddess, huntress"
"branch; shoot (messianic)"
"beautiful, precious"
Similar sound: These names share phonetic patterns with Heydi — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Heydi.
Rhythm: Heydi is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.