Here's a sampling of the different sets included in the mystery bag:
1998-99 Black Diamond
1998-99 UD Choice
1997-98 UD Choice
1995-96 Topps Stadium Club
And the rest (well, most of them).
I tried to get a scan of every different set included and got all but one, which was 90-91 Score and I'm sure we all know what that looks like. All in all, there was a nice mix of cards for only $0.50.