For a deserving challenge, answer, or user that isn't a good fit for any of the other categories.
(Nominated by @Dingus)
The original 60 % accuracy threshold for this challenge turned out to be a little loose . . . and this was the astonishing one-byte answer that proved it.
(Self-nomination by @RedwolfPrograms)
I usually don't do much answering on this site, so I'm kind of proud of this one. I ended up spending a weekend (and a pad of isometric grid paper) on it, as it'd been unsolved for nearly four years.
Also, if anyone wants to try answering it themselves my solution is definitely far from optimal!
My series of 12 challenges to commemorate John Conway
(Self-nomination by @Bubbler)
On 11 April 2020, at age 82, [John Conway] died of complications from COVID-19.
Conway was a truly brilliant mathematician. He made numerous contributions in so maymany fields of mathematics, so much that Wikipedia had to have a dedicated page for the list of things named after him. Among them were three Turing-complete esolangs, which gave me the idea to start this series of Conway-themed challenges on Code Golf.
While I had the list of Conway's achievements, it was definitely not easy to find suitable ideas for Code Golf challenges. Some were mathematically prohibitive, and some didn't have suitable input parameters. Also, I wanted to include challenge types other than plain code-golf, which made things even harder. Fortunately I could pull out two atomic-code-golfs and one fastest-code in the theme.