No, it is not safe to leave the oven on overnight as it can pose a fire hazard and increase the risk of accidents.
No. It is not safe to eat turkey left out overnight in any container.
No. Stew left out overnight would not be safe to eat, covered or not - unless where it was left out was as cold as a refrigerator.
If that 'thing' was a bowl of just potato chips or pretzels - sure it would be safe. But a bowl of chili or soup, a chicken leg, or pizza or anything else that requires refrigeration would not be safe left out overnight. The inside of microwave oven would not afford any special protection against microorganisms.
No.
No, it is not safe to eat deli ham that has been left out overnight as it can lead to bacterial growth and foodborne illness.
No, it is not safe to reuse frying oil that has been left out overnight as it can become rancid and develop harmful bacteria.
No, it may not be safe to eat after being left out overnight.
It wouldn't be safe to eat salad that's been left out overnight.
I left a egg custard pie overnight. Is it safe?
No, it is not safe to eat if it has been left out overnight.
It isn't safe to eat any food that has been left out overnight.