The fiftieth anniversary episode, "The Day of the Doctor", ended with a significant indication that we might see the return of Gallifrey sometime in the next few years. This is something that is long overdue. I understand the idea of making the Doctor the last Time Lord, and thus adding some pathos to the character, but I think there could have been better ways of doing that without destroying (or whatever), Gallifrey. Gallifrey was an integral part of the old series, at least from the time of the Third Doctor onward. The Fourth, Fifth and Sixth Doctors all spent a bit of time there at one point or another, and the Seventh probably would have gotten around to visiting eventually. The War Doctor, as we now know, spent a great deal of time there, but Doctors Nine, Ten and Eleven have all been unable to go. As I said, this is likely to change, and when it does, it opens a whole can of worms for who we might see again. Yes, there's many a Time Lord, and Time Lady!, that we could see back on the series. Here's a list of suggestions for who should/could return, and what actors might make for excellent choices to play them!