The technical term for this ia a *minced oath*, and you may be able to look up a list. The difficulty is that, like other oaths, they are more used in speech than in writing, and, being non-standard, they vary from place to place and among age-groups.  But I have heard *what the deuce, what the flip, what the hey*, and even *what the blank*, as well as the more usual *what the heck* and *what on earth*.