There are a ton of ankle strengthening exercises that utilize either a band or added load, however when it comes to strengthening your ankles all you really need is your bodyweight.
Unlike other parts of the body, your feet and ankles bear all of the load when you are just walking around during the day. For those with weak ankles, your bodyweight is more than enough weight to improve overall strength and function. This is why I am not a fan of doing any ankle exercises either on the ground or seated in a chair.
Your ankles are mobile joints and therefore they should be trained in multiple directions. Below are three "star" exercises, that will achieve this multi-directional training approach to the ankle.
These exercises are in order from easiest to hardest. Aim to go through the exercise two times in a row without falling or having issues before proceeding to the next.
Star Exercises For Ankle Stability and Balance
Exercise #1 - Star Directional Toe Touches
Exercise #2 - Star Directional Deadlifts
Exercise #3 - Start Directional Hops