I've watched all 148 episodes of the Hunter x Hunter anime, and even the movie "The Last Mission." Now I want to know if there is anything else to watch? Are there any more movies, or maybe some new episodes coming out?
The 2011 series covers roughly chapters 1 to 339 of the manga, as documented in this answer by Frosteeze.
In addition to "The Last Mission", another anime film was released in 2013, "Phantom Rouge".
Other than that, you have the original 1999 series, a set of 30 OVA episodes, and a 1998 short film, "Jump Super Anime Tour 98". None of them include material not covered by the 2011 series, as far as I know.