Two 4x3 whiteboards in my home office/study/library. On my laptop I use Sublime. I don't know if others use Sublime the way I do, but what I use it for is, it allows you to create documents that are restored when you close and reopen the app without forcing you to save to a file. That is very useful to me and this is my digital scratchpad of sorts.
I didn't consciously realized until you mentioned it but I use BBEdit as you do Sublime. Each time I come back they're all just where I left off. Used it for that for years.