For me, it's gotta be one of my three daily drivers here at the office: Fostex TH-X00 Mahoganies, Varmilo VA68M, or Mionix Castor.
The Fostex launched right as I was looking to get a bit more isolation than my 558s or 650s. I totally could not resist those wood cups.
The VA68M is my preferred layout since I love arrow keys and page up/page down/home/end. Also made me feel really foolish for buying a Leopold 660M two months prior.
The Castor is a nice upgrade from my Naos 5000. My hands aren't that big, so the Castor fits just right and its a super smooth pairing with the SteelSeries DEX mousepad.