I would think that Sentences 1 and 4 are the more idiomatic usage among the five you listed. Read them aloud to check for yourself:
1. “I caught a cold.”
4. “I got a cold.”
Sentences 2, 3, and 5 can be fixed and made to sound idiomatic by adding the article “the” before the noun “cold” or “colds,” as follows:
2. “I caught the cold.”
3. “I caught the colds.”
5. “I got the colds.”
Of course, these four colloquial expressions of the same idea are also commonly used:
6. “I have a cold.”
7. “I’ve got a cold.”
8. “I’m down with the cold.”
9. “I went down with the cold.”
All of the nine sentence constructions listed above are grammatically airtight and may be used depending on the particular situation of the speaker.
