This is the third version I have published.  The previous versions all worked  fine, just that it has taken some effort to get the counterbores for the mounting screws streamlined enough to please my eye.

This a part I added to an existing design, not sure if that makes it a remix or not, but I don't mind giving credit:

I printed cdsmakestuff's nice ender 3 cooling solution.  https://www.printables.com/model/220082  I chose it because of how well the hot-end shroud fits around the heat sink.   This allows it to work well with the fan reversed, sucking air through the heat sink, with the shroud doing a nice job of forcing the air flow through the fins.  

The reason for doing this is that it drastically reduces the amount of stray airflow on the part when printing ABS.  (although anything is an improvement over the awful stock setup!)  This, of course, will result in the fan running warmer and probably shorten it's life. These fans, though, are not even slightly expensive.  

The shroud and diffuser are now getting warm air from the heat sink instead of cool air from the fan.  This might cause an issue if you print them with PLA.   I printed everything shown in the photos from ABS, and had no warping or fit issues even though I didn't compensate for shrink.  My previous fan housing did a decent job of keeping draft off the parts, but I don't think it cooled as well as this setup.

With the fan now exhausting outward, it “slings” air in a wide cone, with a fair amount going downward toward the build surface.   This diffuser routs it upward, and slows it without creating back pressure. (theoretically a diffuser will slightly lower the back pressure seen by the fan.)

The screw holes and counterbores are dimensioned to fit M3x16 SHCS hardware.  These self-thread nicely into cdsmakestuff's shroud even though sheet metal screws are suggested.

The diffuser transitions from a round inlet that matches the fan, to the rectangular outlet. This was the first time I have used the loft function in Fusion-360.  I can see how it will make some really complex shapes very easy to draw.

I realize that a large driver of cdsmakestuff's design was to eliminate the bulk, weight, and clunkyness of extant solutions. This thing I have added does look pretty clunky…but with 1mm walls, at least it doesn't weigh much.  Pretty is as pretty works.