I've just finished HxH anime and I still want to know what happened with Krollo and his gang and many other things.
The manga has released new chapters since the conclusion of the Hunter x Hunter 2011 anime. The anime ending corresponds with chapter 338 titled "Atop a Tree", currently there are a total of 380 chapters. I will note that if you are not familiar with Yoshihiro Togashi he takes frequent hiatuses from his work on the Hunter x Hunter manga so it is hard to expect a consistent release schedule. You can see all of the hiatuses here: Hiatus x Hiatus. If you would like some more information on the list of chapters that can be found here: List of Hunter x Hunter Chapters.