ReasonReFills.com has been around as long as Reason. It's the home of the World's first ReFill, REX1 and REX2 file products. You'll find info on all AMG's releases plus a few select third parties here too. It's had it's third major facelift in September 2010 and now includes a webstore as well as all the usual info and demo downloads. If you're a Reason user you'll find plenty to interest you here...
ReFill - Propellerheads' proprietary 'instant studio' format. Large banks of everything you'd want in your dream studio in one data file format. Loops, instruments, FX, synth patches and more.
REX Files - Instantly match your track's tempo! Compatible with all major music software. Once you use REX files you'll never use anything else again! Available in stereo and mono versions.