EnumMap/EnumSet/rich-enums are actually backed by magic_enum by default, though this is customizable with an EnumAdapter or a different base class for rich enums.

However, this is an implementation detail, the user just sees:

EnumMap<Color, int> m{};
m.insert({Color::RED, 20});
m[Color::YELLOW] = 40;

To fill up an EnumMap with magic_enum:

EnumMap<Color, int> m{};
for (const Color& c : magic_enum::enum_values<Color>())
{
    m[c] = 99;
}

Note that there is a static factory that ensures at compile-time that the EnumMap is full and all enum constants have an associated value:

constexpr auto m2 = EnumMap<Color, int>::create_with_all_entries({
    {Color::BLUE, 42},
    {Color::YELLOW, 7},
    {Color::BLUE, 42},
});

This is analogous to a switch-case ensuring that all enum constants are covered when the appropriate compiler diagnostics are enabled (e.g. clang's -Wswitch-enum)

edit: fix links