As for the data that can be obtained using Facebook scrapers, they directly depend on your goals. When you scrape Facebook user profiles, you can extract the following info as ID, name, photos, current city, the number of followers, etc. In brief, all the information you may need about users. When you scrape Facebook groups you can also get useful info about the number of posts in the group, the number of likes, comments, main topics of posts, or mentions of certain keywords you need to calculate.
Similarly, you can collect data about mentions of products, the popularity of events based on posts and comments. The possibilities of scraping software are limited only by your needs and the accuracy of key search queries.
For example, Facebook API by Data365 also lets you get extra unique data
like gender and age recognition (via face photos) as well as identification of post reactions that give a competitive advantage in obtained analytics.