The SHERPA partnership of UKHEIs, funded by Jisc, maintains a number of online services to support open access publishing,  including:

• SHERPA Romeo: search by journal title or publisher for a shortcut to authors' options for gold or green open access;
• SHERPA Juliet: search by funder for an overview of their OA criteria for funded authors;
• SHERPA FACT:  search by journal and funder for an instant check on whether the journal's OA options will enable you to comply with your funder's terms.

A key part of publishing open access material is ensuring that readers understand what permissions they have for re-use of the material. The Open Access Scholarly Publishers Association offers best practice guidelines on licensing and attribution in open access:

Beware of predatory publishers who "lie about their business practices for the purpose of attracting paying authors"  (Rick Anderson, 2019).

• David H. Kaye, Emeritus Professor of Law at Penn State, blogs regularly about encounters with Flaky Academic Journals in all disciplines.  You can search the blog content for any references to journals you're worried about.
• The international Committee on Publication Ethics (COPE) has published a discussion document (2019) identifying the key issues and proposing solutions to predatory publishing.
• Cabell's International Blacklist is a "searchable database of deceptive and predatory academic journals".  Access is for subscribers only.  If you encounter any suggestion that a journal has been blacklisted by Cabell's, treat this as a warning sign.
• Hull Professor of Nursing Roger Watson has recorded a podcast (2016) on "steps you can take to protect yourself" from predatory publishers.

Think. Check. Submit. is a tool developed by scholarly publishers and societies,  to offer researchers a checklist that will help them decide if a publisher is trustworthy: