In fact, she has said that the only role she won't play is a variation of herself. When asked specifically what she would not play, Dench said, "Probably an 86-year-old woman who's not able to see."
Related: Judi Dench: Her 5 Best (& 5 Worst) Films According to IMDb.
Going back over this industry titan's career, her analysis is correct. However, there are films out there that were not—or were almost not—graced by the presence of Dame Judi Dench.