This dataset consists of about 32,000 color images collected by the Curiosity rover on Mars between August 2012 and November 2018. The images show various geographical and geological features of Mars such as mountains and valleys, craters, dunes and rocky terrain.
This dataset consists of about 270,000 MNIST-like captcha images. Each 84x30px image consists of 5 alphanumeric characters. I found the dataset useful for testing the UberAI Labs CoordConv method.