ImageNet, GoogleNet, etc. are all image datasets for precisely this purpose. There's also the recently announced YouTube dataset and Kaggle challenge [1] and Google Research's datasets [2].

I agree though, the kind of artificial / play-against-yourself datasets that the folks at DeepMind created for say Alpha Go are an entirely different beast.

[1] https://cloud.google.com/blog/big-data/2017/02/google-cloud-...

[2] https://research.google.com/research-outreach.html#/research...