Magnetic Insoles are pseudoscience nonsense. They are insole with magnets that have made up claims about the health benefits of walking around on magnets.
Most Useful Resources:
Magnetic insoles ineffective for nonspecific foot pain in the workplace (Podiatry Arena)
Magnetic Insoles (PodiaPaedia)
Magnetic Insoles = Snake Oil (Foot Health Friday)
Magnetic Insoles (Foot Health Forum)
Do magnetic insoles work? (Dr The Foot Without the Doctor)
Magnetic Insoles are a Scam (The Best Running Shoe)
M is for Magnetic Insoles (Podiatry ABC)