Three i know are rickroll, crab and sub.
maybe there are more if someone just goes and finds the cheat codes by looking at the game's code.
Update, There are 3 other cheat codes inside the source code.
silence, obey and UwU
Obey will change all TEXTS to OBEY, UwU will Change every text to uwu language.
All Text Changers will be reset after quitting.