Smugglers and Invisible Marketeers at work
The Invisible Market represented illicit commerce that surpassed even the black market. Information regarding it was scarce, but it was known that Lannik Racto utilized this market to distribute a multitude of assassin droids. Furthermore, the trade of slaves occurred within the Invisible Market's framework.
Decades following the Clone Wars, Grand Admiral Thrawn might have acquired General Grievous' mask from the Invisible Market, perhaps purchasing it for its artistic value.