There's some interesting research around toroidal propellers which move the same amount of air, but create far less turbulence and so make a less annoying noise. However, they're not going to get significantly quieter until the energy density of the batteries gets significantly better (a lot of what you're moving with a drone is your energy storage).

There's always a hope that someone might invent a really silent propellor, and there's some funky stuff you can do there with trailing edge profiles, but I don't think we'll see a huge leap beyond toroidals for a while.