No new Revit add-ins debuted on the Autodesk App Store during the week of July 31st. Half a dozen add-ins were updated however, including ElumTools, which received a major update.
STL Exporter 2017
The STL Exporter is designed to produce a stereolithography file (STL) of your building model | Free
About This Version: Version 2017.0, 8/5/2016
STL Exporter for Autodesk® Revit® 2017