Bathroom Stalls

When you're building a community lot they should show up under the items for the specific type of lot. It's generally at the very bottom of the list in the "by type" view of the catalog (I'm not sure if it's actually called "by type" but it's the opposite of browsing the catalog "by room") If you can't find them, you might need to have testing cheats and buy debug enabled turned on.

Good to know! Didn’t even know there were stalls in the sims 4! Lol

You can find them in the build mode.
City Living and Cats and Dogs expansion packs' stalls are unhidden. Others are hidden and require bb.showhiddenobjects cheat.