I use a wok and highest heat for this, so the vegies don't get all wilty. You may need to do this is small batches to allow rapid cooking and prevent unintentional steaming.
Possible vegetables to cook alone or in any combination:
Fresh ginger - about a half inch chunk, peeled and grated
Peanut oil for frying, just a splash for most veggies.
Marinade cubed firm tofu in grated fresh ginger and soy sauce while preparing the other vegetables. It has no flavor of it’s own as far as I can tell.
Add soy sauce and ginger to other ingredients to taste during cooking.
The main thing is to not overload the wok or everything will be too limp and wet. So cook a couple of items at a time and remove from the wok and combine before serving.
Obviously, cooking the hard vegetables first is best. Onions, celery, broccoli, carrots and bell pepper, need more time than canned stuff, tofu, green onions, frozen peas, and squash.
Cook mushrooms separately. Add soy sauce as you go along.