Does anyone think a good Idea for an SCP could be some sort of war drum that causes incredibly violent behavior in whoever hears it?
That idea is pretty cliche. If you think you can make it interesting and add a unique twist, go for it, but that would be pretty difficult. You can try it, but understand that you're exploring territory that has already been explored a thousand times before.
A new idea I had was that it could be a civil war era snare drum that had different effects depending on what rudimentary patterns were played.
Dude, how about the drum leads an army… of toy soldiers… that are out for blood… and then like, depending on how you play it, they go into different attack formations.
I like that one better, I think I will write it!
I think the general lesson to learn is that you should read a shitload of SCPs before you really consider posting something, because ideas like these are a dime a dozen, to be honest, and creativity is key to good SCPs. Check out all the SCPs on the "Top Rated Pages", so you get a general idea on what's been done and what kind of stuff appeals to people here.
New Idea: A book entitled "The Prophet's Handbook" which would detail the usage of a previously unknown language, allowing the user to describe an event, which will then happen later in that person's life.
A repercussion to using this is that a bad side effect would occur. Example: John Smith writes, "I, John Smith, will become a millionaire". Then, 2 weeks later John Smith's Beloved, Rich Uncle, whom he was closer to than any other person on Earth dies leaving a very sad, but rich, John Smith.