The best exercise for the feet is to walk bare feet on the grass in your garden , if possible.
Foot Stretch: Sit on the floor with your legs in front of you. Loop the towel around your feet. Keeping the heels on the floor, pull with both hands. Use the towel to draw the mid foot and toes towards your body. Hold for few seconds, relax, repeat 5 times.
Ankle Stretch: Sit with your legs straight out in front of you. Point your foot down and then bring it towards you as far as is comfortable. Hold, relax and repeat 10 times.
Toe agility: Sit on a chair with a towel on the floor under your toes and stretched out away from your foot. Keeping your foot flat, use your toes to drag, the towel back towards your foot, so that the towel bunches up. Repeat until fatigued.
Foot turn in: Starting in a sitting position turn your whole food and ankle inwards towards your midline. You will feel a gentle stretch on the outside of your calf and ankle. Hold, relax and repeat.
Foot turn out: Starting in a sitting position with your legs straight out in front of you. Turn your whole foot and ankle outwards, away from your midline, so that you feel a gentle stretch on the inside of your calf and ankle. Hold, relax and repeat.