I’ve had success with using a percussion massager (like Hypervolt) on plantar fascsciitis in early stages, and now routinely use it as a quick foot warmup before runs. I used the foam ball attachment
I highly recommend the arch massager at alleviatetherapy.com. I used to use the little spiky balls(which are still pretty good), but the arch massager is much better.
Once I started rehab for my ankle surgery (peroneal tendon repair), I was getting really bad cramping in my arch. I tried rolling the area on different objects (tennis ball, frozen water bottle, little spikey ball meant for PF, etc….). Ultimately, those helped a little bit but what helped the most was finding out I had significant weaknesses in the muscles of my foot/ankle. The stronger those became, the less my arch cramped