GM
General Midi (compatible with other manufacturers as well)
XG
Extended GM, extended General Midi format for Yamaha Instruments
X8
Optimized for Yamaha PSR 8000 and compatible models
X9
Optimized for Yamaha PSR 9000, PSR 9000pro and compatible models
XA
Optimized for Yamaha PSR 1500 and compatible models
XT
Optimized for Yamaha Tyros (mididata with megavoices)
XT2
Optimized for Yamaha Tyros 2 (T2) and compatible models
XT3
Optimized for Yamaha Tyros 3 (T3) and compatible models
XT4
Optimized for Yamaha Tyros 4 (T4) and compatible models
XT5
Optimized for Yamaha Tyros 5 (T5) and compatible models
G1/G
Optimized for the Yamaha Genos Workstation and compatible Models