As already mentioned, you’re probably looking for Obtanium. There’s also APKUpdater, which hasn’t seen updates in two years but has a 3.0 branch ready for testing. (I haven’t personally used it.)
For Liftoff specifically, I’ll add that it’s available in the IzzyOnDroid repository for F-Droid, which is useful if you’re already using F-Droid for anything else.
My biggest (mostly) irrational internet pet peeve is the proliferation of people suggesting “:wq” when “:x” is strictly better.