On linux, at least:

play -q -c 2 -n synth brownnoise band -n 1600 1500 tremolo .1 30

That's nice for drowning out noises when I need to. In case you can't test it out, it sounds a lot like sitting by the beach with waves rolling in. Lyric-less (or nearly) music also works well for me, I just have a playlist on spotify.