How do I find any and all delete-able files on my Mac that are classified as other? My brother installed games on my computer, and even after clearing out "Downloads" and deleting the game applications I have 30 gb of "Other" files that I have no way of deleting because I don't know where they are on my computer.
I assume you're looking at the About This Mac Storage tab; dealing with that "Other" category is tough (illustrated by the wealth of search results for "mac storage other"), as it is comprised of a combination of files in many locations.
A recommendation would be to click the Manage button (Apple Menu -> About This Mac -> Storage) and start with the "Reduce Clutter" option, which may identify unused files that are taking up the most space.
If that option doesn't provide enough items to clear out, a second recommendation would be to try an app like MacPaw's CleanMyMac X, which can identify the files taking up that space to give you a better idea of what can be safely removed.
A more manual (but free and open source) option is something like Grand Perspective, which allows you to visualize the areas that are taking up the most space, but leaves the process of removing them (and knowing how to do so safely) up to you.