I am somewhat tempted by Mastermind, but am wondering how much and what will be good in the current edition.
I don't have my copy handy (guess I ought to buy the PDF myself...
), but whilst I don't find it quite as portable as agency, there's still useful stuff there. Mechanical bits like the senior prestige classes won't fit, but you might use them for inspiration. Mouthymerc already did a bang-up job converting the NPC classes to SC 2.0 NPCs in the License to Improvise forum.
The biggest thing I still find useful is the threat and villain/foil generation sequences which act as a sort of muse when I need villain ideas; they are basically d20 based tables to the tune of AEG's Toolbox
. The one hiccup is that there is a class chart for NPCs that could use updating.