If you’re looking for great datasets to play with, look no further: a massive (and constantly growing) list on Github called Awesome Public Datasets currently features hundreds of datasets. (I considered counting them, but nah…) If you have an awesome dataset you’d like included, send a pull request.
This list comes from an even bigger corpus of awesome lists, called (checks notes) “awesome“. The sheer volume of links to awesome stuff that the awesome meta-list (or mega-list, if you prefer) makes me want to cower in a corner. But if you’re wanting to learn a lot about anything, the awesome list is a good place to start.