I am looking for a graphics card for my Win98 rig that can display this resolution natively without upscaling.
The only two video cards that I found that output a native 512x384 resolution are the Voodoo2 which I use for everything 3D and the Matrox G200 which I use as a 2D card.
The problem with the Matrox cards is the bad DOS compatibility with games. E.g. scrolling issues with Commander Keen and Jazz jack rabbit.
All other cards I tried double the resolution to 1024x768, which eliminates the nice scanline effect when playing on a CRT.

So far I tried:
S3 Trio3D
S3 Savage4
SiS 6326
Nvidia Riva 128
Nvidia FX5900XT
Voodoo 3