Have you upgraded to a newer version of report designer? In the new version, you see just favourites by default, the rest of them are there, you just have to click on them.
If not it sounds like there is an issue with layouts folder either missing or some of it's contents being removed.
Can you check other layouts and see if they are all missing?
The easy way to fix this is to do a Data Only backup.
Then restore a full backup this will also restore the layouts.
Then restore the current data only backup.
Other than that unless you have some other backups the only thing we could do is to give you the standard blank layouts and you would need to customise it to your needs again

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