List of Known File Formats

[puggsoy]

.stm from GameCube games is compatible with VGSC as well, tested it with Paper Mario TYOD. vgmstream lists it as ".stm/.dsp" so I'm guessing they use the same encoding and vary only in extension (I'm not sure of this though).
In any case you can add it to the list, if anybody knows of Wii games with .stm files they're probably the same and can be added to the list too.