I have found some of FAVORITE counseling curriculums for individual and group sessions on Amazon & Youth Light.  I have linked some of my favorites below!  
These are some of my favorite resources to use in small groups.  ALthough they have an age group on there, I have still been able to incorporate many into the middle school level.  Order yours off amazon.com here:
These are two of my favorites for some of those littles who need to keep busy!  Such a fun way to incorporate some fun activities into our counseling sessions!
These are a couple of my favorite girls group curriculums to use! I have used them both with elementary and middle school students! Click below to order them of amazon!