A 2013 study “Open access journal content found in commercial full-text aggregation databases and journal citation reports”…

“A study was conducted regarding the indexing of [DOAJ listed] open access journals in three large, commercially available full-text aggregation databases [EBSCOhost Academic Search Complete; Gale Onefile; and Proquest 5000 International]”

EBSCOhost Complete was the best of the three, claiming indexing of just over 20% of DOAJ-listed OA journals in full-text. As the author says, the marketing claims/lists on this were taken at face value, and were not verified. Nor was the indexing checked for being up-to-date.