Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.
MyNoise - Custom shaped online noise machines. Many Many generic sounds
Text-Generator.io - Self Hostable OpenAI Alternative
Tide - Tide is probably one of the most popular relaxing and productivity boosting platforms available over the internet.
Studiowave - Chillout tunes and inspiration
Sounds of Earth - Listen to relaxing ambient sounds of nature