The case loop earplugs come with is limited and less than ideal to be carried on a keychain. I made my own to replace it :)

This case is designed to securely hold a pair of loop earplugs as well as four "mute" accessories. It's primary closure is via two pairs of 8x2mm circular magnets, but I don't trust them on their own so I designed in a tab detent as well. To open, pull the lid up toward the keyring, then rotate. The screw that holds the case together is also a pivot.