Mezzo roles in operatic repertoire include:

Alceste*, Alceste, (Gluck)
Azucena*, Il Trovatore (Verdi)
Amneris*, Aida (Verdi)
Annina*, La Traviata, (Verdi)
Beatrice, Béatrice et Bénédict (Berlioz)
Brangäne, Tristan und Isolde (Wagner)
Carmen*, Carmen (Bizet)
Charlotte*, Werther (Massenet)
The Countess, The Queen of Spades (Tchaikovsky)
Dalila*, Samson et Dalila (Saint-Saëns)
Dido, Dido and Aeneas (Purcell)
Dorabella*, Così fan tutte (Mozart)
Herodias, Salome (Strauss)
Klytemnästra, Elektra (Strauss)
Laura, La Gioconda (Ponchielli)
Leonora di Gusmann*, La Favorita (Donizetti)
Mother, Amahl and the Night Visitors (Menotti)
Mother, Hänsel und Gretel (opera) (Humperdinck)
Ortrud, Lohengrin (Wagner)
Princess Ekara*(originated role), The Lady or the Tiger (Kirchoff and Leiter)
Princess de Bouillon, Adriana Lecouvreur (Cilea)
Sorceress, Dido and Aeneas (Purcell)
Suzuki*, Madama Butterfly (Puccini)
The Witch, Hänsel und Gretel (opera) (Humperdinck)

Contralto roles in operatic repertoire include:

Auntie, Landlady of The Boar, Peter Grimes (Britten)
The Baroness, Vanessa (Barber)
La Cieca, La Gioconda (Ponchielli)
Erda*, Das Rheingold, Siegfried (Wagner)
Katisha, The Mikado (Gilbert and Sullivan)
Lucretia*, The Rape of Lucretia (Britten)
Maddalena, Rigoletto (Verdi)
Madame Flora*, The Medium ( Menotti)
Mama Lucia, Cavalleria rusticana (Mascagni)
Margret, Wozzeck (Berg)
Mary, Der fliegende Holländer (Wagner)
Mother*, The Consul (Menotti)
Mother Goose, The Rake's Progress (Stravinsky)
Orfeo, Orfeo ed Euridice (Gluck)
Orsini, Lucrezia Borgia (Donizetti)
Pauline, The Queen of Spades (Tchaikovsky)
La zia Principessa*, Suor Angelica (Puccini)
Widow Begbick, Rise and Fall of the City of Mahagonny (Weill)

Concert & Oratorio:

Alto Rhapsody
Cinco Canciones Negras, Montsalvatge*
Kindertotenlieder, Mahler*
Messa de Requiem, Verdi
Messiah, Handel*
Stabat Mater, Pergolesi*
Symphony No 9, Beethoven*
Symphony No. 2 & 8, Mahler
Wesendonckleider, Wagner*
 
 

(*) denotes roles or repertoire performed