what / that thing (used in place of words you can't remember at the moment.)

what number, how many (used with a counter) / (used with も) many (used with a counter)

something

nothing

what is this?

anything; whatever one likes

if you don't mind, if you like, if you're so inclined

above all / no matter how you say it / at any rate / after all is said and done

any

end of a century / end of an era; fin de siècle / (chiefly fiction) end of the world