Well, here is a list of most Saturn racers released outside japan. Some of them are only japan though...
* Sega Rally - Best racinggame ever made
* Daytona USA CCE - Second best racinggame ever made
* Sonic R - fast and fun, looks fantastic, a bit short
* Wipeout 2097 - Much better than the first one
* Manx TT Superbike - Really fast and fun, a bit short though
* Street Racer - 2 - 8 player splitscreen without slowdown
* High Velocity - Good racing game. Some like it, some dont
* The Need For Speed - Very realistic, and loads of options
* Highway 2000 - Quite rare. Looks cool
* Hang On Gp - Kinda like Manx. Manx is better though
* Nascar 98 - realistic but dull game, suits fans better
* Andretti Racing - ok game, nothing more, or less
* Cyber Speedway - nice design, ok game
* Hi-Octane - Like Cyber Speedway
* F1 Challenge - looks nice, real drivers / cars
* Impact Racing - Shoot em up racing game
* Off World Interceptor Extreme - like Impact Racing
* Road Rash - Fun game, looks good
* Scorcher - Futuristic style, good graphics
* Sega Touring Car Championship - Loads of options
* TNN Motorsports - HardCore 4x4 - monstertruck racing
* Tunnel B1 - More shoot em up than racing, but very good
* GT 24 - Good game, some innovative ideas
* Destruction Derby - Fun for a while, lets Bowl!
* King The Spirits 2 - succesor to High Velocity, very good
* Outrun (Sega Ages) - Classic
* Rad Mobile / Gale Racer - Classic, innovative
* Drift King 97 / Syutokoh Battle '97 - race around tokyo, good
* Vatlva - 6 player games, like Micro Machines
* Choro Q - Nice different racing game
There are more though. These are the ones i remember now.
Almost all of those mentioned have two or more player splitscreen modes.