Using Transfermarkt as my source, I rolled up all of the players who are under the age of 23 and whose rights are largely owned by one of CFG's clubs. These clubs include Manchester City, New York City FC, Melbourne City FC, Yokohama F Marinos, Montevideo City Torque, Girona FC, Sichuan Jiuniu, Mumbai City FC, Lommel SK and Troyes (ESTAC).
As I mentioned, I used Transfermarkt as my source, but some values were quirky. For example, many of the players on Man City's U23 squad didn't have any value. The same was true for several players controlled by clubs in lower-profile leagues (notably, Yokohama). Clearly, those players have value; but they must slip through Transfermarkt's algorithms (a.k.a. community wisdom). The poster child for this is Man City's James McAtee, who has no value assigned to him on Transfermarkt. Given that he was twice nominated for PL2's Player of the Month last season, his market value is likely in the six-figure range.
The flip side of that coin is Pedro Porro, valued at $22 million by Transfermarkt. Since City acquired him for about $14 million, that'd be a nice profit... except Sporting - where Porro's currently on loan - have a buyout clause for $10 million. Then again, City originally acquired Porro's rights from Girona, one of CFG's clubs. Complicated.
Anyway, here's the list: