According to Wikipedia:

1870s

• The Slave (1872), private collection.
• Undine (1872), location unknown.
• Gone, But Not Forgotten (1873), private collection.
• The Unwelcome Companion: A Street Scene in Cairo (1873), Towneley Hall Art Gallery, Burnley.
• In the Peristyle (1874), Rochdale Art Gallery, Rochdale.
• La Fileuse (1874), private collection.
• Sleep and his Half-brother Death (1874), private collection.
• Miranda (1875), private collection (assumed).

  

• Two Little Italian Girls by a Village (c. 1875), private collection.
• Portrait of a Young Woman (c. 1875-78), private collection.
• After the Dance (1876), private collection.
• A Sick Child brought into the Temple of Aesculapius (1877), private collection.
• The Remorse of the Emperor Nero after the Murder of his Mother (1878), private collection.
• Dolce Far Niente or The White Feather Fan (1879), private collection (assumed).
• Offerings (1879), private collection.

1880s

• A Flower Stall (1880), Laing Art Gallery, Newcastle upon Tyne.
• Dolce Far Niente (1880)
• The Household Gods (c. 1880), Kirkcaldy Museum and Art Gallery, Scotland.
• Diogenes (1882), Art Gallery of New South Wales, Sydney.
• Summer (c. 1882), private collection (assumed).
• The Favourites of the Emperor Honorius (1883), Art Gallery of South Australia, Adelaide.
• Consulting the Oracle (1884), Tate, London.
• A Byway: Ancient Rome or Winding the Distaff (1884), current location unknown.

   

  

   

• Good Neighbours (1885). Also known as Gossip or The Gossips or Washing Day’. Unknown location.
• Saint Eulalia (1885), Tate, London.
• Esther Kenworthy Waterhouse (c. 1885), Sheffield City Art Galleries, Sheffield.
• Resting (c. 1885), private collection.
• A Flower Market, Old Rome (1886), private collection.
• The Magic Circle (1886), Tate, London.
• Cleopatra (1888), private collection.
• The Lady of Shalott (1888), Tate, London.
• Ophelia (1889) collection of Andrew Lloyd Webber.

1890s

• A Roman Offering (c. 1890), unknown location.
• The Orange Gatherers (c. 1890), private collection.
• Flora (c. 1890), private collection.
• At Capri (1890). Also known as Alfresco Toilet at Capri or The Toilet. Location unknown.
• Arranging Flowers (c. 1890), location unknown.
• Circe Offering the Cup to Ulysses (1891), Oldham Art Gallery, Oldham.
• Flora (1891), location unknown.
• Ulysses and the Sirens (1891), National Gallery of Victoria, Melbourne.
• Circe Invidiosa (1892), Art Gallery of South Australia, Adelaide.
• Danaë (1892), location unknown – stolen.
• A Hamadryad (1893), City of Plymouth Art Gallery, Plymouth.

  

   

• Gathering Summer Flowers in a Devonshire Garden (c. 1893-1910), private collection.
• A Naiad (1893), private collection.
• La Belle Dame Sans Merci (1893)
• Ophelia (1894), private collection.
• The Lady of Shalott (1894), City Art Gallery, Leeds.
• Field Flowers (1894), location unknown.
• Mrs. Charles Newton-Robinson (1894), location unknown.
• Phyllis, younger daughter of E A Waterlow, Esq (1895), private collection.
• St Cecilia (1895), collection of Andrew Lloyd Webber. 
• The Shrine (1895), private collection.
• Hylas and the Nymphs (1896), Manchester City Art Gallery, Manchester.
• Pandora (1896), private collection.
• Mariana in the South (c. 1897), private collection.
• Ariadne (1898), private collection.
• Flora and the Zephyrs (1898), private collection.
• Juliet (1898), private collection.

1900s

• The Awakening of Adonis (c. 1900), private collection.
• Spring (The Flower Picker) (c. 1900), private collection.
• The Siren (c. 1900), private collection.
• A Mermaid (1900), Royal Academy of Arts, London.
• Destiny (1900), Towneley Hall Art Gallery, Burnley.
• Miss Margaret Henderson (1900), private collection.
• Nymphs Finding the Head of Orpheus (1900), private collection.
• The Lady Clare (1900), private collection.
• The Crystal Ball (1902), private collection.
• The Missal (1902), location unknown.
• Boreas (1903), private collection.
• Echo and Narcissus (1903), Walker Art Gallery, Liverpool.
• Psyche Opening the Golden Box (1903), private collection.
• Windflowers (1903), private collection.
• Danaïdes (1904), private collection.
• Psyche Opening the Door into Cupid’s Garden (1904), Harris Museum and Art Gallery, Preston.
• Lamia (1905), private collection.
• The Danaïdes (1906), Aberdeen Art Gallery, Scotland.
• Jason and Medea (1907), private collection.
• Phyllis and Demophoön (1907), location unknown.
• Apollo and Daphne (1908), private collection.
• The Bouquet (c. 1908), Falmouth Art Gallery, Cornwall.
• Gather Ye Rosebuds While Ye May (1908), private collection.
• The Soul of the Rose (1908), private collection.
• Gather Ye Rosebuds While Ye May (1909), Odon Wagner Gallery, Toronto.
• Lamia (1909), private collection.
• Mrs A. P. Henderson (1909), private collection.
• Thisbe (1909), private collection.
• Veronica (1909), private collection.
• The Necklace (c. 1909), private collection.
• Woman Picking Flowers (c. 1909-14), private collection.

1910s

• Ophelia (1910), private collection.
• Spring Spreads One Green Lap of Flowers (1910), location unknown.
• Circe (The Sorceress) (1911), private collection.
• Listening to My Sweet Pipings (1911), private collection.
• Miss Betty Pollock (1911), private location.
• The Charmer (1911), unknown location.
• Mrs Charles Schreiber (1912), private collection.
• Narcissus (1912), private collection.
• Penelope and the Suitors (1912), City of Aberdeen Art Gallery and Museums Collection, Aberdeen.
• Sweet Summer (1912), private collection.
• The Annunciation (1914), private collection.
• The Love Philtre (1914), private collection.

  

• A Tale from the Decameron (1916), Lady Lever Art Gallery, Liverpool.
• I am Half-Sick of Shadows, said the Lady of Shalott (1916), Art Gallery of Ontario, Toronto.
• Miranda – The Tempest (1916), private collection.
• The Enchanted Garden (1916), Lady Lever Art Gallery, Liverpool.
• Tristram and Isolde with the Potion (c.1916), private collection.
• Fair Rosamund (1917), private collection.
• Camellias (c.1910), private collection.
• The Rose Bower (c.1910), private collection.
• Vanity(c.1910), private collection.
• Circe (c.1911), private collection.
• Maidens picking Flowers by a Stream (c.1911), private collection.
• A Song of Springtime (c.1913), private collection.
• The Mystic Wood (c.1914-17), Queensland Art Gallery, Brisbane.
• Dante and Beatrice (c.1915), Dahesh Museum, New York.
• Gathering Almond Blossoms (c.1916), private collection.
• Tristan and Isolde (c.1916), private collection.