Sleep is pretty important.
As it’s such an integral part of human life, many words have been written about it.
This is probably the most famous and recommended book on the topic.
This is like a sleep tracker app with a smart alarm that wakes you up in the right phase of sleep.
This is a noise generator app that has helped me fall asleep many times. It can generate white noise or really any other noise, you can customize the noise shape by drawing manually.
It’s also extremely lightweight and open-source.