You can now request a copy of your Reddit data.
Open link in next tab
Reddit - Dive into anything
https://www.reddit.com/settings/data-request
https://www.reddit.com/settings/data-request
I like that this random 3 year old post popped up.
It's a lot of stuff, like your posts, comments, saved posts, posts you've upvoted/downvoted, messages, etc.