The way I think most people currently handle this is by only keeping ROMs that don't write to SRAM on page 2.

This would include things like The DMG Test ROM or demos. Some very popular choices are found in the assortment of choices in the GBDev music tools file repository.

Another good example is the original Game Boy tetris, which I had to be corrected on a while back as to whether or not it writes to SRAM. So, assuming you have a legal copy of tetris, you could keep that on your second page as well.

fixed

You can have 2 Roms on the card, but only 1 save file. If you try and save a second save file it will overwrite the first one. Hope this helps.

The smart card for GB that kitsch and others sell.. I'm curious how the save feature works. Particularly how the space is used by different roms flashed to the card. If I have lsdj on it, and on the other half I have a GB game with save files, can I trust my lsdj songs to not disappear? Will it dynamically partition space, or.. how does that work? Anyone who can assure me that my songs will not be deleted as I fill my pokedex will earn a digital highfive.