This is a list of all those games on this website for which I could verify the existence of a PC98 version. I have split it into Japanese and foreign games. Most of the games here will run on a PC-9801, some of the latest games may require a PC-9821.
There is a list for PC-88 games as well, but info about that platform is much harder to get.
There are three basic types of PC-98 computers:
For games, only the first two are relevant. Up to about 1990, a lot of games used the 8-color modes, the first two Dragon Knight games for example. Some designers actually managed to dither pastels out of this palette!
The PC-98 models had no native 320×200 resolution. When it was used (for ports of IBM PC games and occasionally for arcade conversions), it was a horizontally pixel-doubled 640×200 mode.
For the RPG series like The Bard's Tale or Wizardry I have only listed the first game so as not to make the list too long. Ultima is a special case, because Ultima 2 was separately ported by Thinking Rabbit (published by Starcraft) several years before the start of the full series by Pony Canyon.