Dee sits next to 5 phonetic neighbors — Di, Dea, and Bea are the closest matches by sound. Most share Dee's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"Goddess; holy one (river name)"
"daughter of the wave or flood"
"land of the south wind"
"son of the noble one"
"from the River Clyde (strong current)"
"noble, distinguished, illustrious"
"enclosed garden"
"rye meadow rider"
"a jewel-bright, exotic feminine name"
"Hardworking, industrious; prosperous"
"from Florence, Italy"
Similar sound: These names share phonetic patterns with Dee — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Celtic origins, giving them the same cultural heritage as Dee.
Rhythm: Dee is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.