eatme – grows characters to twice their size (use at own risk)
Doubles your size, ignoring the menu limit. Goes very slowly at large sizes.

drinkme – shrinks characters to half their size
Halves your size.

normalsizeme – will shrink the character to a somewhat "normal" size
Sets your size to 6 foot, 3 inches. Camera may misbehave and get stuck inside character.

scumsoda –
Sets stamina cost for all attacks to zero.

opensesame – will disable all invisible walls
Removes level boundaries. Walking off the map or into the water will warp you to the default spawn point. Mountains cannot be traversed, but if you walk into one and stop, you'll slide into it, which lets you walk through it. Oddly enough, windmills can be phased through the same way.

dontstopmenow - disable all character-building collision
Removes collision with buildings and boundaries. Moving through multiple buildings at once will slow you down, but never completely stop you. Mountains behave the same as the opensesame cheat. And since windmills behave like mountains, you cannot walk through windmills unless you slide into them (sadge).

fogbegone – [submitted by funnygeeker]
Removes all fog in the scene. Does a lot more than you might expect.

bethekaiju – secret (and janky) first-person camera mode
A very functional first-person view for a secret cheat. Cannot be disabled without restarting or quitting to main menu. Works on custom models, but how correctly configured they are varies wildly. Turning may be difficult at times.

rebuild –
Reloads the city while keeping you in place and retaining your stats. Cheats will still reset. If you had a collision cheat on, you may be warped back to the start point.
WARNING: GPU Load may increase when using this cheat!! This may sometimes bleed into the main menu. If the game feels slow or your fans start running after using this cheat, that's why. Closing the game brings GPU usage back to normal.

clearhighscore – this will clear your local high score (does not work for Steam leader board entries)
Unknown if affects Steam. Maybe in offline mode?

resetachievements – this will reset (lock) all achievements (only works for the itch.io version of the game)
Much less likely to affect Steam.

resetlevels –
Marks Atro City as locked so you get to unlock it again. Works in the main menu. Works on Steam!

webuiltthiscity –
Unlocks Atro City for play. Works in the main menu. And, yes, on Steam, too.