These particular codes are all referenced in EtD's code but their effects are unknown. There's no guarantee they will do anything: the cheat collection function is badly programmed, and it is possible that they were simply wanted to support every combination of four L/Rs in an awkward hard-coded way, without necessarily assigning a functionality to them all.

It's probably no coincidence that this list is in fact every possible combination if you add in the two known codes. So activate them and hype at your own risk :)

L = left, R = right, X = X button.
RRRRX
RRRLX
RRLRX
RRLLX
RLRRX
RLRLX
RLLRX
RLLLX
LRLRX
LRLLX
LLRRX
LLRLX
LLLRX
LLLLX

BONUS CHEAT: Crash the game!
Press any combination of L and R about 17 times to unlock the Crash the Game cheat! As long as you don't press X, you can even exit and enter the pause menu with the start button and continue this cheat from where you left off whenever you feel like it.