Yes here are fillies who'd won TC Races, and the dates

Regret won the KY. Derby in 1915

Genuine Risk won the KY. Derby in 1980

Winning Colors won the KY. Derby in 1988

Flocarline won the Preakness in 1903

Whimsical won the Preakness in 1906

Rhine Maiden won the Preakness in 1915

Nellie Morse won the Preakness in 1924

Ruthless won the Belmont in 1867

Tanya won the Belmont in 1905

Rags To Riches won the Belmont in 2007

No fillies have won the Grand National but twelve mares have won the race:

Miss Mowbray (1852), Anatis (1860), Jealousy (1861), Emblem (1863), Emblematic (1864), Casse Tete (1872), Empress (1880), Zoedone (1883), Frigate (1889), Shannon Lass (1902), Sheila's Cottage (1948) and Nickel Coin (1951).

Fillies and mares are both female horses but fillies are aged 4 years or younger.