It would be wonderful if we could "turn off" hosted feature layers (and even maps!) in AGOL.
This would be particularly helpful when looking back at a half finished project from awhile back - and nothing is named anything that makes sense (ie: test1, test2, etc.). It would be amazing to turn these layers off - and then look in our maps and apps and see if anything broke. Instead of the alternative right now of thinking you made a cohesive list of everything tied to the app - and you delete the rest, and turns out you missed one...
NOT saying that this is something I have ever done...I always give everything descriptive names and detailed metadata... I'm just looking out for those who use "test" for everything! 😃