Just any RPL files really, since RPX is always loaded since it's the main executable, all aoc, content, and saves should be accessible at any time, and most games don't even use secondary RPLs, only ones I know of are Mario Party 10 and amiibo Festival because they modularized it and included all symbols. It *should* work without some but it'll complain if it tries to load them otherwise, since it only loads them when they're needed.
Just wait to see if dimok's discovery below pans out, it should work fine dumped as-is.