I bought Invisible by Damien Savina. It has some good material on there, unfortunately I broke the ITR that Ellusionist provided and I don't think they restock it anymore. It was a pretty decent ITR, I was just using way too heavy of a ring.
If you are looking for something other than ITRs, you can't go wrong with Yigal Mesika's work. Check out the new Loops, Spider Pen Pro, and Tarantula. It's great material. Finn Jon also has some quality material on Loops.