Tilly sits next to 4 phonetic neighbors — Millie, Lily, and Tillie are the closest matches by sound. Most share Tilly's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"strength in battle"
"beloved, wished-for child"
"maiden, girl"
"little red one"
"strong, manly"
"dweller by the swamp"
"youthful, downy-bearded"
"worthy of praise"
"sacred, inviolate"
"all, completely beautiful"
"mother goddess"
"open plain"
"the great sea, vast waters"
"boomerang, curved throwing stick"
"bright lake, shining pool"
"alert, observant"
"seaweed (edible)"
"gracious one"
"white island"
"modesty, faithfulness (symbolic)"
Similar sound: These names share phonetic patterns with Tilly — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Tilly.
Rhythm: Tilly is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.