Sonnie sits next to 5 phonetic neighbors — Sunny, Sonny, and Bonnie are the closest matches by sound. Most share Sonnie's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"sunshine, bright and cheerful"
"God is my strength"
"dew of heaven, my dew"
"spear bearer"
"gracious gift"
"golden, bright yellow"
"theory, to observe (inspired by)"
"bird of prey"
"noble, of the valley"
"a narrative; a tale"
"life, living essence"
"blade dancer, will of the blades"
"complete divine favor"
"the road, the passage"
"grace, unfading"
"beautiful, successful"
"God has promised, promised by God"
"pure, beautiful"
"noblewoman, mistress of the household"
"warlike, strong"
"ray of light, dawn (implied by suffix)"
Similar sound: These names share phonetic patterns with Sonnie — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have English sun + -ie affectionate suffix origins, giving them the same cultural heritage as Sonnie.
Rhythm: Sonnie is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.