For anyone who has lost Apps that worked on Windows 8 mobile and not on Windows 10 mobile. I found the Flightradar24 one that I had previously purchased by following the advice here:
Might work for other Apps.
"I'm sorry to inform you that due to very small portion of Windows Phone users, Flightradar24 was forced to make a difficult decision to stop providing the app through the Windows Phone App store. If you've previously purchased the app you may be able to download and install it still by going to the Store --> My Library --> Apps --> Show all and selecting Flightradar24.
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