Eigenfactor: The Eigenfactor Score is a measure of a specific journal's importance to the scientific community. Scores are based on 5 years of citations. Search by journal name or journal subject category.
Google Scholar journal metrics: Lists of 20 top publications for major disciplines and many subdisciplines. To view your subject's top journals, click "View Top Publication" at the bottom of page, then choose your discipline, and narrow down to subdiscipline, if desired.
Predatory journals are part of an exploitive open access publishing business model involving charging authors publication fees without providing editorial and other publishing services associated with legitimate journals (open access or not).