Definitely for video content. My movie collection that I ripped with Handbrake and other apps is hundreds of GBs. Tiny compared to others. In addition I have a large suite of home videos and downloaded YouTube videos that I keep locally on the device (no adult content, sorry) which adds up to another few hundred GB.
The size of my photo library is also notable, but nowhere near as large. I keep it fairly minimal in terms of what I sync to the device. Random shots are unnecessary. Only the best. I keep a decent bit of music on the iPad as well, my library is 1TB so again only the best. I also have downloaded large sections of North America locally via Google Maps since I don't have a cellular iPad and I like to view maps at a larger size. I could tether it, but no need. Not massive in size, but it all adds up.