Tillie sits next to 4 phonetic neighbors — Tilly, Millie, and Billie are the closest matches by sound. Most share Tillie's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"mighty in battle, strength in battle"
"symbol of purity, virtue, and immortality"
"boundless, unlimited"
"air, song, melody"
"mounted warrior, horseman"
"from the kingdom of Lothar"
"from the marshes"
"mother goddess"
"woodland clearing"
"truthfulness, integrity"
"fair, righteous"
"quintessence, the truest form of something"
"beautiful, rosebud"
"gifted, beautifully unique"
"heather plant (Calluna vulgaris)"
"pearl"
"Ing's beauty, beloved of the god Ing"
"from the wren meadow"
"navigator of the sea"
"white island"
"care, protection"
Similar sound: These names share phonetic patterns with Tillie — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Tillie.
Rhythm: Tillie is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.