4. Mario Kart 8 Deluxe - Booster Course Pass (DLC) [Nintendo Switch]
I always struggle a bit with when DLC is substantial enough to be considered a separate entry. After all, some DLCs are miniscule side things, while others are substantial enough to be entirely separate games. The Booster Course Pass for Mario Kart 8 Deluxe, which gets you all the DLC, essentially doubles the amount of content in the game though, and I think that's enough for it to get its own entry.
I recently subscribed to the Nintendo Switch Online Expansion Pack, and that also nets you access to this DLC. I've now beaten all of the 12 additional Grand Prix on 200cc (the highest difficulty), all with at least a 1-star rank. I think that counts as beating it (plus, beating all of it got me a credits sequence, so there). What can I say? It's more Mario Kart 8 Deluxe, which is a ton of fun. I really enjoyed the tracks, particularly of course my childhood favourites that returned like Waluigi Pinball and Wii Rainbow Road. Having new characters like Pauline is of course fun too. But it's literally just more Mario Kart 8. Mario Kart 8 is fantastic, and after not having played it for a while it was nice to return to it, but whether or not you'll like this is entirely dependent on how you feel about Mario Kart 8. If you like Mario Kart 8 Deluxe a lot though, and you want something to get you back into it, this DLC is well worth checking out.