I'm a huge fan of simple meals that don't involve a crock pot. There are so many variations on stir fry, that you can eat a distinctly different tasting meal every day of the week. You can even combine the two to help with meal prepping.
Brown a flank steak in a pan. We're not sealing in juices - we're making a crust. Throw it in the slow cooker for a few hours. Check to make sure it's tender. Prep some veggies by cutting and portioning them in containers. Find a stew sauce that's simple. When you're ready to eat, saute your veggies in a little oil, and add a generous portion of sauce when your stir fry is near complete. Throw in the meat towards to end to heat. Serve over potatoes or rice or something simple.