I worked freelancing in 3 industries, and in one industry I only made $200. Do I file that one or does it count as less than the required $600 for filing?

Yes - You count that one. The IRS requires that you report all income received.

The $600 you mention refers to the fact that, if you make less than $600, the employer doesn't have to issue a W-2 or 1099.  [But you still have to include it in your income.]