Is there a website that lists the journals that are actually scams?

There used to be one, called Beall's list, which listed predatory journals. The author however took it offline, apparently partly because of legal threats. If you search online you will be able to find archived copies of the list, but as far as I know these are not updated any more. You can read about it here for example.

There are at least a couple of lists. You'd have to judge for yourself how much you trust them since apparently none of them is affiliated with a University or some other "reputable" curator:

• List of Predatory Journals

  This is a list of possibly predatory journals. The kernel for this list was extracted from the archive of Beall’s list at web.archive.org. It will be updated as new information or suggested edits are submitted or found by the maintainers of this site.

• BEALL'S LIST OF PREDATORY ​JOURNALS AND PUBLISHERS (Last updated December 31, 2016)

  This is a list of questionable, scholarly open-access publishers. We recommend that scholars read the available reviews, assessments and descriptions provided here, and then decide for themselves whether they want to submit articles, serve as editors or on editorial boards. In a few cases, non-open access publishers whose practices match those of predatory publishers have been added to the list as well.

The Wikipedia entry Predatory open access publishing has some good information also.

While it does not specifically list journals as being predatory, "SCImago Journal Rank" is a good indicator of the reputation of a given journal. Their extensive listings can be found here:

http://www.scimagojr.com/journalrank.php

It is a free alternative to the older "Impact Factor" rating system. The "SJR indicator" like "Impact Factor" uses the number of citations to articles in a given journal to rank the journal's importance. The difference is that in the SJR system a more prestigious journal citing another journal carries more weight in ranking that journal. Also only more recent citations are included in the ranking system. This is similar technology to Google's "PageRank" system.