"Slice" is a very useful generic concept for clearing out the fridge. It's so generic that it doesn't have a name besides just "slice". It could be spinach slice, or zucchini slice, or mixed veggie slice, or many other things.
The idea is that you locate all the non-watery veggies that need using up. Clean them and grate them or chop them or whatever. Spinach, chard, silverbeet etc should be lightly steamed, then squeezed and chopped. I find that zucchini can be grated then squeezed out to remove excess water. Some mashed pumpkin is good, or precooked cauliflower or broccoli. Defrosted frozen spinach can be used, too. But no tomatoes in the mix, they are too wet!
Anyway, you pop them in a big bowl. Add any odds and ends of cheese that you have, grated if it's firm. Cheddar, ricotta, and cottage cheese are good basics, but there's nothing to stop you using fancy bits of brie or gruyere. Then add some cooked rice - one of those sachets of precooked rice from the supermarket is handy here, if you don't have leftovers and don't have time to cook it. I like to make this with brown rice.
Chuck in some flavouring agents. I like to use plenty of dill and lemony herbs like sumac and lemon myrtle, and some chopped spring onions. But perhaps some fresh basil and garlic might suit your fancy better. I usually like to make it fairly mild, and then add some chutney or sauce to taste at serving time. You can add other little bits and pieces of stuff for an accent - leftover antipasti, a handful of pitted and halved olives, some chopped sun-dried tomatoes or roast capsicum. If you're not cooking for a vegetarian, some chopped ham or cooked bacon pieces could well go in.
Now have a closer look at your bowlful of stuff. Will it fit into your shallow casserole dish or pie plate for baking? If it looks like too much, then scoop some into a storage container to freeze for next time. If it's not enough, add another grated zucchini, or some frozen spinach or frozen peas or something.
To finish off, take 4-8 eggs, depending on the size of the dish. Break them in, and mix well. If they're a bit old, because this is also good to use up excess eggs, then break them into a cup first to check that there are no bad smells. Put all in your oven dish and top with sliced tomatoes if you want, maybe some breadcrumbs for crunch, and definitely some grated cheese - more cheddar, or some parmesan. Bake at 160C until the egg is set - 30-60 minutes depending on the depth of the baking dish. Don't rush it with a high temperature, or it will tend to separate and get watery.
Serve it in big slices, like a lasagne. This is a complete meal in itself, with veggies, protein and carbs all together. But it's good to have something else alongside for variety. That could be a nice crisp salad, or any side vegetable, or even a sausage for the meat-eaters, or a slice of smoked salmon - that's especially good if you've gone for lemon and dill as your flavours.