For a list of identified predatory publishers/journals, refer to:
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: