Drac's PDF Viewer
Real thumbnails for attached PDFs, and a viewer that opens right on the page - no new tab.
Version 1.5.0 - for XenForo 2.3.13+ - $5.00 on its own, or $20.00 for all six Drac's Shop add-ons
What it does
XenForo shows an attached PDF as a plain file icon, and clicking it...