Sentinel 2 imagery
Optical images of the ocean surface offer stunning views of ocean waves including whitecaps and other features. You can go to the S2 bot for a wide range of examples. The data can be dowloaded from the Copernicus Science hub, you just have to register.
The MSI sensor uses 13 "channels" (think of them as "colors") and series of 12 detectors, each detector acquiring teh 13 channels and each with a slightly different view geometry. The small differences in acquisition time and view geometry between the channels and detectors can be used to look at things moving on the ocean surface.