I use this one:
=TEXTJOIN(", ",TRUE,ArrayFormula(IF(ISNUMBER(FIND(I$2:I$18&" ",D2&" ")),I$2:I$18,"")))
I2 through I18 is list of strings.
D2 is the value you're testing against.
Really useful for tagging cells based off a list of tags. Gives a comma separated list.
I just discovered that YouTube has this built-in now! Next to a video there are three dots, if you click them, you get this menu:
If you click "Not interested" it shows this:
and then if you click "tell us why" you can block recommendations based on a video you watched:
If you click "Don't recommend channel" it shows this: