Be sure to file this one under 'proceed with extreme caution' folks, because a comprehensive mod for Mario Kart 8 Deluxe is available now.
Dubbed CTGP (Custom Tracks Grand Prix) Deluxe, the mod offers up a bunch of tracks not previously available in the base game and official expansion, including some third-party goodies that, frankly, have us scratching our heads a little bit. You've got the likes of Wario Shipyard from Mario Kart 7 and Luigi Circuit from Mario Kart Wii, but also Walrus Cove and Jungle Falls from Diddy Kong Racing, and even Windmill Isle from Sonic Unleashed.
The download page for the mod is just a quick Google search away, but the kicker with this one (in case it wasn't already obvious) is that you'll either need a modded Switch to run the content or use a Switch emulator like Yuzu. Judging from Nintendo's recent action against both paths, we wouldn't necessarily recommend it.
In fact, the CTGP website warns that accessing the content and "putting your console at risk" is entirely your own responsibility. In addition, it has temporarily disabled online play and wireless play due to issues involving bans and changes to the netcode. Local multiplayer, however, works just fine.
It's an impressive endeavour, adding a total of 14 new cups and 56 additional custom tracks, along with an OST of remixes courtesy of the CTGP music team Cochu (director and producer), Nah Tony (producer, guitarist, and bassist), and TJ Campbell (saxophonist).