If you've never played in a Manly jersey then you don't count, i.e. OMeley, Gimp, Muir, etc. Never compare Beaver to any nuffie who only played for the northern eagles, that's disrespectful.
Anyway list of players post NE who went on to play for other NRL sides as follows, you work out whether any of these reached any level of greatness
Albert TORRENS
Phil BAILEY
Andrew KING
Ben MACDOUGALL
Nathan LONG
Luke DORN
Aaron CANNINGS
Ben WALKER
Sam HARRIS
Ian DONNELLY
Chris HICKS
Paul STEPHENSON
Kane CLEAL
Jeffrey ROBSON
Michael WITT
Travis BURNS
Matthew ORFORD
Adam CUTHBERTSON
Glenn HALL
Shane NEUMANN
Jack AFAMASAGA
Michael BANI
Jared WAEREA-HARGREAVES
Trent HODKINSON
William HOPOATE