Plenty. Don't confuse playing a different role to getting better either.a player who makes lasts longer than 6 years.
In fact I can't think of many players who became regular 22 who didn't end up better than they were at end of yr 3.
Can you?
Gunston for one was much better in year 4 than 3, and looks to still be improving
David Makay is a great candidate, Brent Reilly another. Heath Scotland a prime example of a person who just platued but was able to create a career at the level he got to.
Plenty of crows to pick from.
To make it easier for you. You can pretty much look at any "under rated" player.You know the honest trier who never really gets the awards of his more talented peers.