Storms - The stronger and louder the storm, the better. I love hearing thunder too but it's mostly the rain and wind that calms me down.
Fire - As in a small campfire. The quieter, the better for me.
The general noisy sound of being in the middle of a city. I wanna live right off of a really busy street because it's easier for me to fall asleep when I hear the cars rushing by.
The sound of my computer running. It's almost just white noise but it has a specific sound that calms me more than plain, old white noise.
And then sounds that make me very uneasy are the ticking of clocks, human voices (but not animal), anything very, very low in pitch, and anything that's in close proximity to me (besides my computer).