Some of my current PCs at my table are doing the following:
Deal with the Demonic Embodiment of Lust: In the setting, each of the seven deadly sins is personified by an individual demon. This character made a deal with Wrath to gain one set of powers during her back story (Inhuman abilities for the most part), and after the contract was completed, she was given a new deal with Lust. The character now has Sponsored Magic (mostly mental whammies, emotional aspects, and summoning via EvoThaum).
If needed, physical enhancements might come into play.
"Super Soldier Serum": This is a concept an old player of mine asked for my help to plink out for his game. Basically take the idea of the Super Soldier Serum as we know it (i.e. Captain America) and make it a bit more negative. He was thinking more Resident Evil (specifically, use the Hunger Track, but require an injection of an anti-virus to clear it), as it could also allow various mutations as a way of going the NPC route.
I was looking more at Mr. Hyde; have a Human Form with "Beast Change," with compels when he is "stressed" to cause the change, and further compels to act according to that darker nature when he is transformed (or even add Demonic Co-Pilot).
Descendant of a Deal-Maker: One of my current players is using this for a Victorian-era game. His character is from Russia, and his great-grandfather made a deal with a Steppegoblin (think a form of a Fae) to have access to certain powers for his family. The contract can be renegotiated, so when he tires of Glamour and Divination, temptation will come knocking. . .