Almost anything can be made in a slow cooker, the key is not to add anywhere near the amount of liquid that the book or recipes say.
Here's a few of my favourites;
Stew,
Use a cut of meat suited to slow cooking (lamb neck, braising steak, chicken thigh, pork shoulder)
Then an accompanying herb and liquid,
Chicken - white wine, sage
Lamb - red wine, rosemary, mint
Beef - ale, bay
Pork - cider, sage, fennel
All these can be done with a splash of stock or any other liquid instead.
Chop meat into bitesize chunks, dust with seasoned flour.
Add any veg chopped into chunks all around the same size (carrots, celery, onion)
Then add a splash (half a cup at most) of your chosen liquid.
That's the basic stew, cooked on low for as long as possible, serve with Crusty bread or mash and fresh steamed veg. If it needs thickening after a good stir then a spoonful of gravy granules will do it.
You can add mustard, applesauce, cranberry sauce etc for added flavour.
You can cook a whole pork shoulder in 1/2 cup of apple juice on low for as long as possible, then shred it and add bbq sauce and serve in baps or wraps with salad and cheese.
Same for a whole chicken, stuff with herbs and add in the SC, no liquid and cook for about 6hrs on low, you can then brown in the oven if you want crispy skin.
You can also do baked rice puddings, baked potatoes in foil, fudge, cake, bread.
Curry, bolognese, chilli, Shepard's/cottage pie, pie fillings.