I don't know if there's some standard symbol to represent the Power Set in Latex. According to Wikipedia there are some possibilities:

I think the first one would be the most appropriate because the second one is used for probability, the third one represents positive numbers, the forth one is the symbol for Weirstrass's elliptic functions, and the last one is used for structures and sigma-algebras. The problem is I think this first "p" is ugly, at least to my taste. I wish there was some alternative to it, for example I really love the symbol that Suppes and Halmos use in their books:

Does this symbol exist in any package?
Note: It would be nice if Weirstrass's symbol existed in form of uppercase letter, this would be a good alternative I think.