Can I play everything that is copyright free on twitch or does twitch have special rules.
Twitch even "bought" some titles, if so where is a list of the pieces.
Can't I play songs because they're too "bad"?
These are all my questions!
The best thing to do is to read the Twitch terms and conditions.
You can play anything you want during your steam. However, you can also choose that your streams can still be seen on your channel for a few days. In these videos it can happen that the part where Twitch sees protected music cuts out the sound. (You won't hear the music, your voice, or anything else)
with "bad" music I would be more careful on Twitch.
All my statements without guarantee. Copyright infringement can quickly become expensive, so read the Twitch terms and conditions again
So only for the correct position:
There's no copyright free music because music always has an author.
There's a maximum license free music, which you can use accordingly.
But be careful here too - if the music becomes licensed at some point, you will need to remove it from your video.