Image Retrieval will be a good choice.

Basically you need a GPU to speed up when you process your image data (constructing relevant machine learning models).

And nowadays when talking about information retrieval, it is always under the context of big data.

Realtime data processing (eg remote control of robot, or any other use) is a suitable area for GPU, used for gaming where realtime matters.

Information-driven decision making based on real-time measurement strategies would be a interesting area. Even, the use of GPU to solve situations (through matrixs) related to scenarios, multiple states, the relationships with the monitored concept, etc in the measurement process would have a lot of applications.