These codes unlock new cops based on YouTubers (I think, I couldn't find any other info). Press L to display the password menu, enter the code, and click "OK".

ave
zuevmustfall
angrycops
coxncrendor
pressheart
friendship
bleach
trilby
spaceoddity
zekethethird
ko
eyedrops
tomatotactics
ocarina
ninelives
pyrobarbare
meridian
huntpack
doppeld
thankyou
biginjapan