Neither here nor there - of no consequence or meaning, irrelevant and immaterial. Example - "Whether you go to the movie or stay at home is neither here nor there" "Your comment, though interesting, is neither here nor there"
Catch-22 - a dilemma or difficult circumstance from which there is no escape because of mutually conflicting or dependent conditions. Example - "The choice you're giving me is a catch-22 because, no matter which option I choose, I'm not going to be happy with either one."
Out of the frying pan into the fire - from a bad situation to a worst situation. Example - "When I tried to argue about my fine for a traffic violation, the judge charged me with contempt of court. I really went out of the frying pan into the fire"
Bargaining chip - something that can be used to gain an advantage when you are trying to make a deal or an agreement. Example - "The workers used the threat of a strike as a bargaining chip in their negotiations"
Different strokes for different folks - different people like different things. Example - "My neighbor spends all of his free time working in his garden. I would never want to do that, but different strokes for different folks."
If worst comes to worst - if the worst possible thing should happen. Example - "We should be able to catch the 4:30 train, but if the worst comes to worst, we could get a taxi and still get into town on time.
To stand one's grounds - to refuse to be pushed backwards, or to continue in your beliefs in an argument. Example - "Clare stood her ground in the meeting and refused to be intimidated even when Michel got angry"