The Undermine content update in World of Warcraft offers players a chance to build reputation with the Cartels of Undermine Renown faction and its four constituent Cartels: Bilgewater, Blackwater, Steamwheedle, and Venture Company.  Reaching Renown tier 13 unlocks the weekly C.H.E.T.T. List, typically redeemed for 250 Valorstones.

However, a hidden function of the C.H.E.T.T. List allows for significant reputation gains.  After turning in two completed lists to C.H.E.T.T. in the Incontinental Hotel, players earn the "C.H.E.T.T.ing It Twice" achievement. This unlocks the "Finder's Fee" option with the designated Cartel quartermaster for that week, allowing players to exchange completed C.H.E.T.T. Lists for 500 reputation points with that specific Cartel.

While World of Warcraft periodically adjusts its paid services to enhance player experience, this hidden C.H.E.T.T. List feature offers a strategic advantage for reputation building.

Players receive one free C.H.E.T.T. List weekly, with the option to acquire an additional list for 40 C.H.E.T.T. Cards. These cards drop from enemies and rare spawns within the Undermine zone and the Side Street Sluice Delve.  It's worth noting that utilizing C.H.E.T.T. Lists for reputation does not contribute to the "C.H.E.T.T. Mate" achievement, which requires turning in 100 lists via the standard Valorstone method.

Exchanging C.H.E.T.T. Lists for reputation offers long-term benefits, as the value of Valorstones diminishes throughout the season, while Cartel reputation gains through weekly tasks are limited.  This hidden feature is not explicitly mentioned in-game, making it crucial for players to visit their Cartel quartermaster if reputation gain is a priority.

Important Note: C.H.E.T.T. Lists cannot be redeemed with Darkfuse Solutions LLC, the fifth hidden cartel in Patch 11.1.  However, Market Research, which contributes to Darkfuse Solutions reputation, can be earned through various Undermine activities.  This allows players to simultaneously progress their Darkfuse Solutions reputation while working on C.H.E.T.T. Lists or farming C.H.E.T.T. Cards.