During the Phillies' glory years, Manny Trillo was a good one. As good a fielding second baseman as there was in the late 70s/early 80s (I think he had the record for errorless chances at one point) and had a few clutch hits here and there. Ain't nobody outside of Philadelphia and maybe Cleveland remembering him, though.
Good God. I just looked at his baseball reference.com page. Never realized he lasted until 1989. Thought he fizzled after the Phils threw him in in the Von Hayes deal. Dude played 17 years in the majors. Damn.
And speaking of longevity, howsabout Julio Franco as a character player?
Garry Maddox was another good one. Great center fielder. In my mind, I can still see him lanking after fly balls at the Vet.
I've always thought of Tim Wakefield as being in this category, too. Guy's been a rock for some pretty good Red Sox teams, been around forever, but never has (and never will be) better than a No. 3 starter.