This sounds like a job for ... Electronic Spell Checker!
If you don't have one you can download WordNet 2.1, a freeware dictionary developed by Princeton Univ.
There are a number of front-ends for WordNet (and it comes with its own so you can use it "out of the box") but EBswift (http://www.ebswift.com/) offers a great freeware-donateware package that allows you to do all kind of dictionary searches through the database.
An on-line version of the dictionary is here. (http://www.ebswift.com/WordNetAspNet/Default.aspx) A wildcard search like *x (in the advanced search mode) would turn up all words that end in "x." Of course, you'll have to hunt through the list.