So Sims did that annoying thing where it decided to randomly uninstall some of my many, many Sims3Pack downloads, so I had to do that annoying thing where I reinstall the entire folder I have of DLs, but when I went to empty my recycle bin after deleting the downloads files from the launcher instead of in the file folder, it says it's already empty- however, I can't run the game because I suddenly only have ~50 MB of available disk space. I'm extremely strapped for disk space right now but I've had all of these installed before (just last night!) and I even went through and deleted over half of my old saves, each of which was taking up a ton of space, way more than the total space all of my downloads combined took up. I think the game is storing the deleted downloads somewhere other than my recycle bin but I cannot locate them to delete them.
@witchmark I'm not sure what you deleted and what you didn't, so I'll describe all places the data is stored. When a Sims3Pack is installed, its file in Downloads doesn't disappear, which is probably how you reinstalled. (These files can be stored on an external hard drive if you want; the game doesn't need them to be in Downloads.) If the original downloads were compressed, you probably still have the .zip or .rar files somewhere too, maybe in your system's Downloads folder. And when you uninstall content from the launcher, its data doesn't disappear from the .dbc bundle in DCCache into which it was installed. The content becomes hidden, but the .dbc file stays the same size.
It's also worth combing through your in-game bin, when you have a chance, and deleting old households and builds you don't need. These files are stored in Library inside your game folder. Uninstalling a cc household or lot should remove its entry from Library, but you can check the folder itself for extra files. These can also be stored on an external and transferred back to Library when you want to use them. The files can be renamed as well, so you can keep track of what's what.