Noodles: I used udon noodles, but you can pretty much use any Asian noodles you have like rice noodles, vermicelli noodles, glass noodles. Dare I say, you can even use spaghetti if it's all you have! And if you want a low-carb version, you can use zucchini noodles or any other spiralized veggie.
Veggies: You can use anything you find in your fridge or freezer like broccoli, spinach, cabbage, kale, mushrooms, or other Asian greens.
Tofu: You'll need firm tofu, that has been pre-pressed. Otherwise, make sure to squeeze it to remove the access water. You can use 1 cup of edamame beans instead.
Leftovers: Store them in the fridge for 2-3 days in an airtight container. When it's time to reheat them, put them in a microwave or back into a pan, adding some water or vegetable broth to loosen them up a bit.