I discovered this wonderful site recently - https://mynoise.net/noiseMachines.php
The site has several different categories of "noises" to choose from such as Tonal Drones(Indian, Northern Lights, Singing Bowls, Tibetan Choir, etc.), Natural Noises(Rain, Wind, Distant Thunder,Waves, etc.), Industrial Noises(Railroad, Laundromat, Traffic, Fireworks, Aircraft Cabin, etc.), Atmospheres(Subaquatic Dreams, Church, Sailboat, Spring Walk, Fairy Pond, Tibetan Spirit, etc.). And many, many more.
The best part is the player has faders which allow you to control the mix or you can animate the faders and have the mix change over time. I've tried having more than one tab open with different sounds playing simultaneously, such as Tibetan Choir playing with Singing Bowls. Pretty cool.