where can I find workout programs to change up things for my clients.

You will have to base your program design according to your client’s fitness goals and assessment. I see you have a lot of experience in the medical field, so you will need to base your exercise prescription according to the results you get from the above information. You can search for various routines and exercises online, but they have to be relative to the goals and capabilities of the client. Otherwise why would others need you as their trainer?