I got some Kyronaut Thermal Grizzly for a recent 9900K upgrade, seems pretty good, just now seen 26c at idle with a few browser pages open. That's only with a cheap Pure Rock CPU cooler with extra fan mod as well, temporary until I get a Dark Rock one or better, but it's doing the trick pretty well so far.
Only point to note is it was quite weird consistency to the point I used the recommended spreader technique rather than a blob or IMB X that I'd usually use. Have to say, I actually quite liked the spreader technique for feeling assured of coverage before putting the heat sink on.