Moddex - CAD Support
(you can also go direct to this registration page)
These files do not yet take advantage of some of the advances made in Revit 2013, that I posted about last week. However, Moddex are "looking into fast tracking the upgrade".
I also recently downloaded the free Railing families from BIMstore. Again, these are not upgraded for 2013.
Don't forget to check out the online 'master list' of Revit content at Links to Revit Content online. If something is missing, please register and add it to the page.
A while ago, I posted some in-place and component Stairs and Railings.
If you have any particularly great Railing families that you would like to share, feel free to reply using the comments!