Really changing it up, I'll take the 2001-02 Pistons. The year before they started their great 6 year streak. They were decent, but never great throughout the 90s with Grant Hill, but had just done a sign and trade with Orlando to at least get something back for him, rather than losing him in free agency, and wound up some a couple of nobodies in Ben Wallace and Chucky Atkins.
Instead the shocked everyone with Jerry Stackhouse, and a bunch of guys nobody wanted to win 50 games, and nearly have the #1 seed in the East. They just had a ton of guys with roles, Ben Wallace, Clifford Robinson, Chucky Atkins, Jon Barry, Michael Curry, Corliss Williamson, Zeljko Rebraca. In a sport that is superstar dominated, the fact that that roster finished second in the conference is crazy. I remember being mad when they tinkered with it, but it turned out for the best, won a title two years later when they traded Stackhouse for Hamilton, traded picks for Rasheed Wallace, drafted Mehmet Okur, signed Chauncey Billups, which relegated Atkins to a backup, drafted Tayshaun Prince. But my high school years 98-02, was my prime NBA fanhood, the guys I was friends with at the time were really into it, I played a ton of basketball then, we watched it every Friday night, but the Pistsons weren't good. So for that to all come together my senior year of high school, kind of my last year with that group of friends, really added to the whole thing.