Oh hell yes. Have you ever fried up a batch of Lasagna from the night before or enchiladas? Yumm. I usually put on a huge pot of chili and pressure some beans and we eat on that for days. You can make burritos, enchiladas, huevos rancheros, refritos (refried beans - made with cheese, garlic, chili pequin, butter, and pepper), etc. It's cheap and delicious. The beans are an excellent source of protein.
I also make a mean roast marinated in coffee and vinegar. You cut slits into the meat and insert garlic and onion pieces. Marinade overnight and then cook in a cast iron dutch oven. I add potatoes, carrots, cherry tomatoes, pearl onions. It lasts for days and the meat just falls apart. You can make a tasty gravy from the marinade.
I also make a huge batch of salsa. The longer it sets the better and hotter it gets. We use it on eggs, tortilla chips, nachos, quesadillas, tacos, breakfast burritos, etc., etc.. The list goes on and on. So, yes, I am a big fan of leftovers.