xcydcn if you have problems downloading specific extension, could you leave a comment on that extension's discussion?
Sometimes the extension authors delete their code from GitHub and never say they did on the forums. In that case all we can do is mark the extension as "abandoned" on the forums so people don't try downloading them.
We don't keep copies of third-party extensions, but if you really need the code you might be able to find it in your own backups if you ever copied the entire vendor
folder, or you might be able to find other users who kept a backup of the original code.