There are a few chords with a wide variety of notations. One obvious one is a minor chord with a maj7th interval added to it. This chord has been called : mL7. m maj7, m natural 7, mi raised 7, m #7, m triangle 7 and m with a slash through the 7. All the m notations can be mi, min or -. All the major notations can be ma, M, maj or triangle. In a key, you can also use a notation like Cm add B.
It's most famous use is in a minor chord progression where the root descends by half step.
The chord has also been casually identified as a "spy" chord. Think James Bond!