One thing to note is that enabling any of the cheats does disable the ability to earn achievements or trophies, but there is a Steam Workshop mod to circumvent this, if you want to fully embrace the cheating lifestyle. There is no restriction on how many of these you can have on at any one time, so you could enable them all and enjoy an entirely restricted gameplay experience if you wanted. There are currently five available cheats in Cities Skylines to enable, and they are as follows:
They are grouped in with any other mods you have downloaded, but an easy way to find all the cheats if you want to turn any on or off is to sort by author, as the cheats themselves will be the only ones without an actual creator so will sit at the top.