Gertrudis

Also occasionally used in Spanish-speaking countries as a masculine name, though most bearers would've been born before the mid-20th century and much of its masculine usage was concentrated in Latin America rather than Spain.
One example: Gertrudis García Sánchez, soldier and Mexical Revolution participant who was governor of Michoacán from August 1914 to February 1915 (https://es.wikipedia.org/wiki/Gertrudis_G._S%C3%A1nchez)

Gertrudis is actually the latinized form of Gertrude. As such, it has often been used in The Netherlands in the past.