I consider all journals to be predatory, to an extent: https://www.researchgate.net/post/Are_all_journals_predatory_and_can_we_make_it_so_that_we_benefit_from_our_own_work
That being said, there are so many journals that are exceptionally abusive, that are not well respected and have as their only goal the collection of your money. I’ve been curious about riojournal for a long time, because my research does not conform to a lot of the standards of academia.
Many are call to research papers: https://www.researchgate.net/publication/330182836_Call_to_Research_A_need_for_a_new_paper_format
But their open access fees don’t seem all that cheap, which concerns me.