Are these sentences correct? Can I use them when referring to an object/thing?

Question

1. I thought I wouldn’t find them.

2. Imagine if I hadn’t found them.

3. What if I hadn’t found them.

4. What if I hadn’t find them.

5. What if I didn’t find them.

6. What if I didn’t found them

Answer 1

4 and 6 are both very wrong.

No 5 isn't right either.

Answer 2

1. I thought I wouldn’t find them. Correct.

2. Imagine if I hadn’t found them! Correct.

3. What if I hadn’t found them? Correct.

4. What if I hadn’t find them? Incorrect.

5. What if I didn’t find them? Incorrect.

6. What if I didn’t found them? Incorrect.

Yes, they can be used to refer to an object / thing.

Answer 3

4 - is incorrect, "hadn't" is not grammatically compatible with the simple present "find"

6 - has the same problem

Answer 4

4 and 6 really suck.