I think your statement that
I know that it not legal to earn revenue from a different source other than the company associated with your OPT.
is somewhat misleading. You can associate multiple employers with your OPT. From the OPT Policy Guidance document , the following applies to the regular OPT period:
A student may work for more than one employer, but all employment must be related to the student's degree program and, for pre-completion OPT, can not exceed the allowed per week cumulative hours.
And for the STEM-extension period, should you qualify for that:
A student may work for more than one employer, but all employment must be related to his or her degree program and all employers must be enrolled in E-Verify.
In short, having two employers simultaneously is certainly possible, assuming this is properly reported. Hence, working for both Amazon and Twitch should be possible in principle, with some caveats
- Would streaming really count as related to your major? You'd need to check that with the international office at your university.
- If you're on pre-completion OPT, you're limited to 20 work hours per week. Might be difficult to find time for a second job.
- Working at Amazon or Twitch, you might have contractual restrictions to take into account.
Most likely, #1 is the real sticking point. I have no data on this, but it seems very likely to me that USCIS would not consider the 'performing' aspect of Twitch streaming as related to a major in say computer science.
My understanding is that all income from Twitch would be considered working, including donations. I'm not 100% sure if this applies to donations or not, but realistically speaking, we're most likely talking about a small sum compared to a respectable software engineering salary so don't risk it. If you cannot successfully argue that streaming is related to your major, yet still want to stream, it's probably advisable to remove all forms of monetization.
 Old document, but still in effect, see this. May contain some outdated references to 17-month STEM extension.