SMF2 Grass edition like it's name is suggesting is built just for grass levels (athletic and cloud levels are also possible). It contains SMB1,SMB2,SMB3 and SMW grass tilesets as well as SMB3 wood and athletic tilesets. SMW athletic tiles are kept in this edition. It contains a few music to choose from besides the ones already mentioned above it also has a SMB1 The Lost levels title screen music and SM64 main theme as well a SMB1 overworld theme remix.
You can also play a level made in this edition by downloading the notepad file.