Active Release Technique and the Graston Technique are both soft tissue mobilization techniques originally developed by Chiropractors. Active Release Technique (ART) uses the therapists hands occasionally with specific patient movements to address soft tissue dysfunction. I have seen little data supporting its efficacy, but I haven't looked very hard, either.
Graston is a type of instrument-assisted soft tissue moibilizaiton tehcnique that is similar to Augmented Soft Tissue Mobilization (ASTYM) which was devleoped (at Ball State, I think) by an MD and a PT. Both techniques use insturments (metal for Graston and ceramic/acrylic for ASTYM) to deliver pressure to soft tissue to promote proliferation of fibroblasts and also to help with fiber orientation. Here is a link to a review of literature regarding soft tissue mobilization. It was done by Don Strack, a Regis University OMPT Fellow.
https://connect.regis.edu/p78856226/