Sometimes copying popular games can be endearing and these titles definitely had the right idea at the time even if none of them could beat their top rival, to qualify for this list you must have power ups in the game, must have memorable characters and with a couple of exceptions must at least take some elements from Mario Kart.
Honorable Mentions
Nicktoons and Cartoon Network Racers: Both competed for the same crown but largely unmemorable
F1 Race Stars: Worthy attempt from Codemasters using super deformed F1 Drivers but the game physics are severely annoying.
Toy Racer: Spin off game to Toy Commander, too small to be anything significant.
Snowboard Kids: It's snowboarding but it at least it's worthy of mention.
Sonic Drift: Doomed by being a Game Gear exclusive but not bad for a first try.
Bomberman Kart: Forgettable but at least well designed.
Re-Volt: Other than power ups it uses physics too close to actual RC Racing and being sentient cars rather than characters means it can't go on this list but it's worthy of mention.
Vigilante 8 and Twisted Metal: Disqualified by virtue of being a battle game with cars rather than a racing game.
10. South Park Rally
The cast of South Park racing around town trying to reach checkpoints as opposed to following a simple track, the physics were solid for an N64 era racer but frustrating difficulty hindered the experience. South Park is a lot more sophisticated these days so something like this feels dated.
9. Pac Man World Rally
Pac Man has always had a go at every genre and with a few friends managed a decent outing as a racer but not nearly as solid as Ridge Racer.
8. Dreamworks Superstar Kartz
With challenging circuits and a colorful cast of characters, Dreamworks pulled off a surprisingly good kart title only let down by poorly designed AI.
7. Crash Team Racing
Crash had a few attempts at this and all of them played surprisingly well but largely forgettable characters these days doesn't give it much of a legacy.
6. ModNation Racers
The idea was to create your own experience and they nailed it, but very much a short lived trend riding on the success of Little BigPlanet.
5. Cars II
A surprisingly well built attempt from Pixar, and pretty much a no brainer, just a little let down by track choice but the cast of characters more than make up for it not to mention some interesting weapons to boot.
4. Konami Krazy Racers
The only one on this list that feels closest to the Mario Kart experience in terms of aesthetics and overall design, even the cast of characters are built on the same design of weight classes but stops itself from being an outright clone by some clever track designs.
3. Blur
This is the gritty Mario Kart, the one sold as a solid adult experience making it the exception to the rule, it's Mario Kart with real licensed cars and it was awesome, even now long after the companies that published this game abandoned it, the online community keep it going.
2. Sonic and Sega Allstars Racing
While the first game was good, the sequel was incredible, it didn't settle for imitation it took it to a professional level by challenging the most fierce of Kart Racers where perfection is the key to victory, I would put this number one, accept.
1. Diddy Kong Racing
This game is the only kart racer in history to compete against Mario Kart and fight it on a level playing field, the plane and boat functions that inspired Sega Allstars Racing's sequel started here and even Mario Kart these days has never managed to create the same experience Diddy Kong Racing did.
