First of all FDIC is really just an agreement amongst all the banks to support eachother. In full meltdown its useless. Really it wouldn’t take that much for it to happen in our mad fractional reserve, derivative, structured world.
Second, be very careful about money market funds. Many are able to offer those 5% returns because they are buying mortgage securities and the like. The fund can drop below $1 nav.
I guess the safest is short term treasure bills which you can easily buy at Treasury Direct. Other then that foreign currencies and gold. IMHO.