These were designed by Ariel Hart and are on her Tumblr, here.
I don’t recall if there’s ever been an official Simpson emoji set, but if there were, I suspect we’d have seen it when the movie came out. A fan can only wish these were available for use–even if there are some post-season 10 icons in the mix here.
Ariel has lot of great work on her blog, it is well worth a look. If you need work done, she is freelance!