Fantastic list. I just want add one to this sublist. I use these often:

9. Find files tips

find . -maxdepth 1 -type f -printf '%f\n'

-printf '%f\n': This is a function to print in a formatted manner, typically used in C or other languages. %f means here print the filename only, without directory or slashes. And add a newline off course, but you could also print it by space enclosed between quotes: "%f" I prefer this over executing separate echo process.

-type f: This will limit the output depending on the filetype you define. Here f means files only. This can have multiple types too, in example directories or executables.

-maxdepth 1: Do not search subdirectories, only look in current directory like ls does. You could specify more depth too. And there is even -mindepth 2 in example, if you want to skip some top level directories and only search somewhere deep. This makes sense if you have organized structure of directories in example.