Hi ziggywizard89, Those aren't toolbars or plugins. They are built-in to the configuration of Firefox as available search engines.

No! I have all of those uninstalled and have for years. The plug-ins dont appear on the add-on/plug-in option in the menu. The only way I know that they are there is because I use IOBit Uninstaller and IOBit Advanced System Care. System Care shows me that I all of a sudden have 6 new browser plug-ins. It sends me to Uninstaller and I delete those plug-ins, which I have to close firefox to do. Uninstaller shows them deleted but a few seconds after restarting firefox they show up in the IOBit Uninstaller Toolbars and Plug-ins submenu again.

Menu -> Options -> Search -> One-Click Search Engines

Yeah, the only one there is yahoo.

Hi ziggywizard89, in Firefox 68, the built-in search engine plugins changed from .xml (OpenSearch) files to .xpi (extension) files. However, they are still stored in a program file and can't be easily removed from Firefox. I don't know what IOBit is trying to do, but I'm not sure I would trust it to modify a program file.

What is it that you would like to do?

(A) Hide the search engine plugins from the search bars?

You already are doing this, I think, through the One-Off Search Engines box on the Options page.

(B) Disable the search engine plugin extensions?

You can do this using a policies.json file. That will instruct Firefox to "uninstall" those extensions every time it starts up. They can't actually be removed from the program file this way, but they will no longer be active in your session.

This article describes where you put the file: Customizing Firefox Using policies.json (usually C:\Program Files\Mozilla Firefox\distribution\).

This is the policy -- assuming you want to remove them all:

{
  "policies": {
    "Extensions": {
      "Uninstall": [
        "amazondotcom@search.mozilla.org",
        "bing@search.mozilla.org",
        "ddg@search.mozilla.org",
        "ebay@search.mozilla.org",
        "google@search.mozilla.org",
        "twitter@search.mozilla.org",
        "wikipedia@search.mozilla.org"
      ]
    }
  }
}

After saving the file and restarting Firefox, the about:policies page will show the list of uninstalled extensions (see attached screenshot).

I don't think IOBit will understand, but that's not my concern...