I got a query from a colleague who monthly needs to print many documents from a folder in a document library. This was taking them a lot of time, and they asked me to enable 'something' to print all the documents at once. There are commercial products to achieve this, but for tens of documents there's a free workaround.
Here are my documents in O365 (though this is identical in 2013, and 2010);
Simply click on the venerable 'Open with Explorer' option;
In explorer you can select up to fifteen documents at once, and a print button remains visible. This cuts down the work of multi-document printing a lot! The documents can't be mixed, so this doesn't work for e.g. PDFs and Word together, but you can sort on the Type column to get everything into one batch.