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"
"word, speech"
"work of God, God's labor"
"melodic blend with '-nelly' (meaning light or torch, from Norse)"
"moon goddess, huntress"
"God has healed"
"the queen"
"place name of Guanche origin, meaning unknown but likely related to..."
"my God is an oath"
"whole, universal"
"beautiful flower"
"joyful, happy"
"alive, living"
"literary creation; joyful, beloved"
"orchid flower"
"orchid flower"
"watchtower; to watch over"
"determined protector"
"dear little rose"
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.