Dead or Alive 2 Cartridge with Naomi Motherboard is a fighting game in the Dead or Alive series.

Virtua NBA is a Basketball Sim game, published by Sega, which was released in Japan in 1999.
 

Sega Tetris brings the Game Boy classic to the Dreamcast. Expect the same fundamental gameplay here: tetris blocks of set shapes drop from the top and you have to line them up on the bottom, forming lines that disappear. This port of the arcade game features 2 new modes. The Versus mode is playable online over Sega.net, so you can challenge other players who has access.

Power Stone is a fully 3D arena fighting game series made by Capcom. 

 

Two of the best-known companies in 2D fighters combine forces to release Capcom vs. SNK for the Dreamcast. There are 14 characters who have been taken from the series of Street Fighter, King of Fighters, Fatal Fury, and Samurai Shodown. 

 

Naomi Jamma I/O board allows you to plug a Naomi system into any JAMMA cabinet.

Guilty Gear follows the story of ten combatants entering "The Second Sacred Order Tournament" for reasons of their own. Set in a bleak future in which its present time has just recovered from a 100-year-war against man-made bio-organic weapons called "Gears". A Gear named Testament began a plan to resurrect Justice and wipe out the human race.

Zero Gunner 2 is a 3D multidirectional shooter developed by Psikyo as a sequel to Zero Gunner, the original arcade game. It was released for the Dreamcast in Japan in 2001

The gameplay consists of shooting enemies who come in one of two polarities: either black or white. The player's ship can be either polarity, and can be switched at will. Treasure previously experimented with colors and polarity in the Sega Saturn title Radiant Silvergun as well as Silhouette Mirage, released for both the Saturn and the PlayStation. Ikaruga was well received by critics.

As there are so many fantastic fighting games emerging recently -- especially the incredible Street Fighter IV -- it's difficult for me to give a wholehearted recommendation to King of Fighters '98 Ultimate Match. With that said, this game will probably please fans of the old-school stuff, especially considering the fact that Ultimate Match includes the original King of Fighters '98 on the disc, along with an extra disc with plenty of wallpapers and other goodies. And for only 20 bucks, it's definitely not a bad deal.