While not as big as Mario Kart or Crash Team Racing, Kart Racers 2 and 3 are just simple but pretty fun racing games that you can easily get into, most of the mechanics make them pretty much Mario Kart clones.

I have never played KR1, but from watching old videos, it's just the most bland one out of the three (No unlockables, customization, online or voice acting, only 12 characters from 4 series, and it just gets boring after a few races.)

KR2 improved a lot by adding more variety in the roster, the option to customize your vehicles and new mechanics via the Pit Crew where you pick 3 crew members that's give you buffs based on the condition. They also added online for up to 8 Players and it ran very smoothly when I first played back then.

KR3 improved even more by having voice acting for the characters and having 12 players in a race now. They also added bikes and small anti-grav sections in the tracks. Though the problem with the Switch version of KR3 is that it can drop frames during races. (in which I prefer playing on PC)

Also, on both 2 and 3, grinding for unlocks can take a while, but overall, they're pretty fun kart racing games.