I've updated my android app Jumble Solver after a user commented that it couldn't do wildcard letters, such as a blank tile in Scrabble.
Took a couple hours overall, but it was easy enough to implement. To use, you just put '?' in for the blank tile, and it will solve it. Now my app is even better.
Try it out! https://play.google.com/store/apps/details?id=jopo.JumblesSolver