Reason supports wavs aif and soundfonts. They also support rack extension which are 3rd party plug ins quite a few of them are ported vsts like U-He's Uhbik series, Rob papen's Predator and Distort, Softube Fet Compressor, the rough rider compressor and some others that I cannot think of. What Reason does not support is vst/au/rtasI'm pretty sure Reason doesn't support stuff like that .... I'm not entirely sure about drum kits, since they're just .wav samples .... but I know Reason doesn't support third party plugin's .... that's why I never made the commitment to change to it.