The biggest thing that comes to mind is @Eugene’s Joseki Explorer
Notable mentions also include:
@Flovo’s chat shortcuts
@RubyMineshaft’s improvements to game history
and my upgrade to auto adance
There were countless other improvements, probably some more notable than those I’ve mentioned, but these immediately came to mind
Also, expected very soon (in the next week or two, I believe) is @anoek’s upgrade of our AI from LeelaZero to KataGo, which will afford us numerous possibilities moving into the future to upgrade our score estimation and auto-score features.