Foundational Data types that enforce no opinions on how to build games and provide many facilities that complex games need. This largely avoids graphics and physics, but provides tools like the SortedVector, CountedPtr and HashedString classes.
Actually, I should rewrite these requirements when I am not sleep deprived, but in general other operations that return booleans is a decent idea for at least one operator.
Add more bitmask operations for the BitfieldTools. There should be an && and an || that return booleans.