This article shares the exciting discovery of previously unidentified arias within the music amassed by the eighteenth-century English poet Thomas Gray. His ten-volume collection, now held at the Lewis Walpole Library, Yale University, contains some of the only surviving copies of important arias dating back as far as 1690 and bears many annotations by Gray listing performance venues, composers, opera roles and singers. One volume of the collection contains many unattributed works, among which I identify a number of arias. Five of them match the libretto to La caduta del regno dell'Amazzoni (1690) and another corresponds to Il Colombo overo l'India scoperta (1691), both operas originally set by Bernardo Pasquini. The texts of the two ensuing arias align with Carlo Sigismondo Capeci's libretto for Ifigenia in Tauri (1713), the opera he wrote with Domenico Scarlatti for their patroness, Maria Kazimiera Sobieska. In addition, in the first pages of the assemblage, instructions in Gray's hand on how to execute a basso-continuo accompaniment continue from another volume, where he entitled these ‘Regole per l'Accompagnamento’ and interwove them with a ‘Toccata per il Cembalo’. This article seeks to describe the newfound works and stimulate study into the full contents of Gray's music collection, but its main focus is on the two excerpts from Ifigenia in Tauri and their possible attribution to Domenico Scarlatti. Salient characteristics of these scores are presented, as is an evaluation of their concordance with Capeci's libretto. Further, I underline features that these numbers share with other Ifigenia in Tauri arias known to be by Domenico Scarlatti and provide comprehensive tables detailing equivalent structural proportions.