I think that skaters who didn't achieve greater fame after leaving Zero (or Powell) shouldn't count. So Marisa or Wade Burkitt aren't good examples.
I've always considered Think (post Drehobl) to be the most minor-league of teams - developing talent before their riders make it to The Big Show with another company, or even worse where players stick around to toil in obscurity (Danny Fuenzalida, Jake Nunn, Sean Payne...).
Think at one time or another had:
Duffman
Joey Guevera
Brain De La Torre
Liard King
Diego the Butcher
Lee Yankou
Bachinsky
and even love-to-hate-ems like Cody Mac and Manny Santiago.
These aren't all superstars, but they all moved on to greener pastures after Think.
Toy Machine has also farmed a lot of big names including Muska, Tysahwn, Bam Bam, and even the Chief.