i haven’t found many of the usual electronic massager tools to be really useful.  there are some more professional ones that work a bit better, like the DMS (direct muscle stimulator).  they are unfortunately a lot more expensive.

personally i’ve played with a vibration plate and lacrosse balls and supernovas, as well as banded distraction mobs. it works really well. for example, put a ball on the vibration plate, then lay on it to hit something like your t-spine and have the vibe plate on, then go through movements. it works better than just being on a static floor and smashing.  i’ve also setup myself during mobs on the vibe plate – for example, for a hip mob, i put my foot on the plate, setup the band at my hip, and then go through mob movements. the vibe goes up my leg via the foot and helps release the sticking points.