A blacklist identifies sites known or highly suspected to be untrustworthy.
“Blacklists and whitelists share the same problem in that they attempt to externalize an evaluation process that is best internal, contextual, and iterative.” (Swauger, 2017)
Jeffrey Beall, a former librarian, collated a list of potential and possible predatory scholarly open access journals. However, this list was last updated in 2017. Researchers could refer this archived list to find out if the journal/publisher is blacklisted.
The list of possible predatory publishers was based on Beall's opinion and it has been continued to be widely used.
Other blacklist of journals:
Review of Cabell's list in the resources below: