We consider the Corsair LL120 to be one of the best PC cooling fans, at least when it comes to those with RGB. This version comes with a Lightning Node Pro RGB control, too, for more intense control ...
Compare this to a single one (with no RGB controller) at $19. This AIO cooler has a 280mm radiator and two 140mm fans, so it should fit most towers while also providing an absolute ton of cooling.