Hold on, are we talking about the same Onyx Edition Risk here? I'm starting to think there's some confusion—Risk, the classic board game, doesn't have an official 'Onyx Edition' as far as I know. You might be mixing it up with something like 'Risk: Legacy' which had its own deluxe features, or maybe an obscure third-party collector's version. That said, if such a thing existed, 'exclusive features' for a premium board game would usually mean things like weighted metal pieces instead of plastic, a neoprene mat instead of a paper board, maybe a special carrying case or unique faction tokens. But without an actual product to reference, this feels like chasing a rumor. I'd double-check the source of that edition name, because it doesn't ring any bells from the mainstream hobbyist community.
For truly exclusive premium board game features, you'd look at companies like Petersen Games or Chip Theory Games—they do things like acrylic standees, laser-cut wooden inserts, and foil-stamped rulebooks. But Risk? Its special editions tend to be themed, like 'Risk: Star Wars' or 'Risk: Game of Thrones'. I'm leaning toward this being either a fan concept or a misremembered title. If you find a link or a photo, though, I'd love to be proven wrong!