SRB2Kart – Quite possible the best skill based kart racer ever [PC only]
https://mb.srb2.org/addons/srb2kart.2435/
This is such a tight controlled kart game, that has no right hiding in obscurity. Seriously, check it out if you don't mind dealing with some wonky setup. It's totally worth it. I think the OG CTR is still my favorite though.