There is an Export syntax that lets you specify the elements being exported. This appears to be ignored by "PDF".
plots = Plot[#[x], {x, 0, 1}, ImageSize -> Large] & /@ {Sin, Cos, Tan};
To print each of plots to a PDF page the syntax is
SetDirectory[$UserDocumentsDirectory];
Export["plots.pdf", {"Pages" -> plots}, "Rules", "AllowRasterization" -> False]
ResetDirectory[];
However, the resulting PDF places the list (with curly braces) on one page of the PDF.
Any ideas how to get this to work? Mind you this is in version 10.4 on Win 7 Ent as version 11.1.0 always crashes if I try to Export PDF even after reinstalling.
Update: WRI has responded and said that "PDF" "Pages" Export is not currently supported. A similar workaround of creating a notebook with page break cells was provided.

Import, non forExportYou should look for printing environment styling If you wish to set the margins, paper size, etc for output document. – Rom38 May 16 '17 at 08:33"XLSX"in the Elements section and notice how the"Sheets"element is documented. You canExport"Sheets"for Excel files. In"PDF""Pages"is documented the same as"Sheets"in"XLSX". Therefore, it stands to reason that you should be able toExport"Pages". – Edmund May 16 '17 at 10:57"Sheets"is not undocumented. Read the documentation. – Edmund May 18 '17 at 18:34