Sure! Here are the tag questions for your situations:
You are walking over a wooden bridge with your friend. The bridge looks rather old and some of its parts are broken. You say: (not / very safe) This bridge isn’t very safe, is it?
You and your friend are outside the restaurant. You are looking at the menu through the window. The prices are high. You say: (expensive) It is expensive, isn’t it?
You’re listening to the radio. A man is singing well. You say: (a good voice) This man has a good voice, doesn’t he?
A bear escaped from the zoo and you’ve heard about it from the news. You say: (be / dangerous) A bear can be dangerous, can’t it?