Ok..so send your scout to region likes Spain, France, Germany, England and Portugal. In my games, the regens are a lot of them coming from Europe country. These are the clubs that have produce the good regens.
Argentina: Velez, Racing, Boca, River and San Lorenzo
Brazil: Santos, Gremio, Sao Paolo, Palmeiras, Cruzeiro
Colombia: Atletico Nacional
Cameroon: Coton Sport
Chile: Colo colo, Universade (spelling maybe wrong)
England: Arsenal, Chelsea, Man Utd, Aston Villa, West Ham, Leeds, Tottenham
Germany: Bayern, Leverkusen, Wolfsburg, Werder Bremen, Dortmund, Aachen
Portugal: Porto, Sporting, Benfica, Braga
France: Paris, Monaco, Lyon, Marseille, Nice
Spain: Real Madrid, Barcelona, Sevilla, Valencia, Villarreal, Athletic
Mexico: Atlas, Cruz Azul, Pumas
It is more than these about the list of clubs that always produce a good regen. The regen actually presented start in season 2009-2010. You just go to Big Clubs and see their player ages in 1st team squad. If there are player under 20 in 1st team squad, they actually are the good regens.