For the NES, add multirom. Its unused but works; I myself have never gotten it to work however.
"While only compatible with the NES Virtual Console container, if multiple NES binaries are placed within the /rom/ directory of the Virtual Console RomFS and modified appropriately to run, when you start the application, you'll be presented with a menu in which you can explore the Virtual Console's RomFS contents and boot a different game, although to change the game you're playing does require you close and restart the application." from tcrf.org