While your whole routine would not be based on isometric exercises, they are a great way to isolate and also to pre-fatigue muscles before you go into your usual routine.
For example, squatting against a wall and setting the timer for 1 minute before you go and do your barbell squats will ensure your glutes are already on fire! It also recruits your deep abdominal muscles to maintain the hold.
Here are your moves. How Long Do I Hold? As Long As You Can.