Via Google Scholar

Olivia Pratt from F1000Research replied (27 June 2022) that "The way you search for reviewers is very similar to how we do it when we have to occasionally suggest reviewers, so you are doing it perfectly. In case you are interested, we also find that using Google Scholar to search for collaborations is particularly helpful, (using the author:"" author:"" formula), as it can often pick up the articles/research that haven’t been indexed in PubMed, which is particularly relevant for the non-biomed, med related articles that we also handle." Example use: 'author:"A Cavanna" author:"K Black"'.