@Clark and I decided to move most extensions to the Friends of Flarum team. Those that haven't been moved over either will be in the future or aren't a valid candidate to be kept maintained.
I will close this discussion and refer you to the flagrow.io search listing to see whether extensions are now available under different vendors. Once flagrow/backup is moved over to my personal namespace hyn, the flagrow namespace will no longer hold any maintained extensions.
Those extensions that are available on github under a MIT license can be commissioned for an upgrade or forked to be patched.