Maybe not as elegant but another possibility would be to write a formula to do the check and fill it in an adjacent column. You could then filter on that column.
The following looks in cell b14 and would return true for all the file types you mention. This assumes that the file extension is by itself in the column. If it's not it would be a little more complicated but you could still do it this way.
=OR(B14=".pdf",B14=".doc",B14=".docx",B14=".xls",B14=".xlsx",B14=".rtf",B14=".txt",B14=".csv",B14=".pps")
Like I said, not as elegant as the advanced filters but options are always good.