Sorry for the late response, anyways.
You need to download WinRAR (If you haven't) It automatically makes the add-ons you download as zip files.
If you have it downloaded, you can easily make a zip file by right clicking - new - zipfile (I might be wrong, Mac users might not have that function, but it wouldn't matter)
If you got add-ons that are folders, download them again. They should appear as a .zip file when you have WinRAR installed on your computer.
If you delete your add-ons folder, they will be reinstalled again with default add-ons just by launching blockland.
You should only have one Add-Ons folder in your documents or wherever the blockland directory is. The folder should exactly be named "Add-Ons" It may work both ways, but, it is recommended. Trustlist has nothing to do with Add-ons.