2: The advantages and disadvantages. The fors and againsts. The pros and cons. The pros and antis.
3: He reconsidered. He had different opinions. He had another thought. He had second thoughts.
4: He's recovering from the flu. He's on the fiddle. He's on the mend. He's on his bike.
5: They are reasonably rich. They are well to do. They are well and good. They are counting their blessings.
6: It happened completely unexpectedely. It happened on the bounce. It happened out of the blue. It happened out of thin air.
7: She's really fit! She's fitter than a bell! She's as fit as a fiddle! She's as fit as a drum!
8: Don't complain about a present. Don't look at the horse's teeth. Don't ask about the price. Don't look a gift horse in the mouth.
9: She very nearly bought the house. She was on the brink of buying the house. She was on the edge of buying the house She was on her toes about buying the house.
10: He accidently revealed the truth. He let the dog bark. He let the bird out of the cage. He let the cat out of the bag.
11: It made me think. It was a penny for my thoughts. It gave me food for thought. It gave me my thinking cap.