These are the new ones and their effects:
198 Whack a staff
borovan- not sure
220 Rink Runner
happyvalley- not sure
368 Hasee bounce
pleasegivemeonemillionneopointsthankyouhasees- does some animation during gameplay
371 Trouble at National Neopian
stardust- possibly a copy&paste error from faerie bubbles
500 Meerca chase
fly- ???
507 Ice cream machine
invincibility- makes you literally invincible but you are not allowed to send score
600 Ruins Rampage
blackpawkeet- probably another copy&paste error
615 Jolly jugglers
magicjugglingballs- extra life (once per game)
627 Caves and Corridors
freetime- pauses the timer (once per game)
gimmeabreak- extra life (once per game)
nomorerocks- makes all rocks disappear
772 Dubloon disaster
jboogie- (during main screen) shows old animation
pooltoy- ?
showfps- shows fps counter
Please confirm my findings.
Also, try to find the effects for others.
Can you find more for the newer games? Crisis Courier, Bumble Beams, Snackrifice, Shenkuu Warrior (those are what I call new because they don't have much documentation)