Deepweb is just the parts of the web that aren't indexable or searchable - like your bank account login. There are lots of social networks that could be considered deepweb, including parts of Facebook. I think Discord might be deepweb as well.
Darkweb is a subset of deepweb that is typically served via tor/onion. Facebook even as a darkweb address. It's been awhile since I played with it, but there's several chans on there.
It's slow and boring though.