AAX (Avid Audio Extension) is Avid’s new advanced plug-in format for Pro Tools systems. Many plugins already have AAX versions, in addition to RTAS and TDM versions. Meanwhile, several plugin developers are working to add compatibility to their existing products. Here are some resources to help keep track of AAX compatiblity of various plugins and software developers.
Avid AAX Plug-in Compatibilility http://www.avid.com/US/resources/AAX-plug-in-compatibility
Sweetwater 64-bit AAX search https://www.sweetwater.com/store/search.php?s=s%3A64-bit-AAX&Go=Search
For further discussion, with other users, check out Avid AAX Forum.