What are the most common weaknesses that can lead to injury? What are the best exercises to address these weaknesses?

I'm kind of at a point where I'm reevaluating how I am training all around to enhance my longevity. After recent knee issues, I want to ensure I can stay in the game for much longer. Many people just follow an exercise plan but many plans are imbalanced and can lead to injury in the long run. There are many exercises people just don't do that which would be very beneficial for them.

In my own case I was recently prescribed by physiotherapist to do clamshells to help with the knee pain. These are killer and this definitely helps address a major weakness for me.

What are some other good exercises which can be used to prevent injuries and address common weaknesses?