Auditory tools
Jeff Bridges Sleeping Tapes (for sleep)
Brainwave Music (for focus)
A Soft Murmur (for focus; reduce distractions)
Noisli (for focus; reduce distractions)
Video Game Music (for focus; sleep; meditation)
Les Bruits de Paris (for focus; isolation)
Window Swap (for focus; isolation)
Tree (forest sounds for focus; meditation)
Movie soundscapes (a YouTube search with lots of options)