An interesting example of someone who managed to produce two unrelated "sleeping beauties" in different fields is the German mathematician Grete Hermann. Her Ph.D. thesis in the 20s gave effective algorithms for many questions in abstract algebra. I think her motivation was philosophical, that an effective algorithm is better than an abstract existence result, but it wasn't considered that interesting of a question until computers were invented and computer algebra developed, and then immediately several of her algorithms became the state-of-the-art at the time.

Unrelatedly, she wrote on the foundations of quantum mechanics, and showed that a "theorem" of John von Neumann, which would have ruled out later research by Bohm and Bell if it were correct, was false three years after he published it. Bohm and Bell had to independently rediscover that the result was false years later.