As both you and I already hinted at, you can get a name in a different TLD (or even prepend "get", e.g. "getAPP.com"), but you're taking a hit for a variety of reasons (perception, confusion). My point was only that you won't ever replicate it, and for that reason domains are unique.
My personal favorite "fallback" is to use .io or prepend "get."
But I would absolutely stay away from any cctld's like .io. If your site becomes popular you will end up having to purchase the .com assuming you even can do that. (Once publicity of your .io site gets out the price of the .com will go up if it's even possible to buy).
My personal favorite "fallback" is to use .io or prepend "get."