Oh man you have no idea, LESSON TIME
0.5x, 0.75x, 1.5x, 2.0x, 3.0x, 4.0x, 5.0x, 8.0x
boost,
wave,
drunk,
dizzy, space, mini
hidden, sudden, stealth,
blink,
beat,
tornado
mirror, left, right, shuffle, supershuffle
little, reverse, note, flat, plain
noholds, nofreeze, dark
0.7xmusic, 0.8xmusic, 0.9xmusic, 1.0xmusic, 1.1xmusic,
1.2xmusic, 1.3xmusic, 1.4xmusic, 1.5xmusic
anything that I bolded you can slap a % onto and make it do it by that much (goes by % of the BPM). Also, any installed noteskins you have can be used as valid mods

You can also apply these mods to nonstop courses as well:
#MODS: TIME=(the second count of the song):LEN=(duration):MODS=(modifiers):
#SONG

as usual);
example:
#MODS: TIME=20:LEN=20:MODS=beat500%:
#MODS: TIME=40:LEN=10:MODS=wave;
also this thread has been stickied for future reference to anyone else who's got questions about courses
#SONG:test/CANON-D:HARD:3x;