How to remove category link from redactor links but leave assets and entry link This is a follow up from How to remove Link To Category from Redactor.
I've been able to setup the module and remove all links with this:
Event::on(
  RedactorField::class,
  RedactorField::EVENT_REGISTER_LINK_OPTIONS,
  function(RegisterLinkOptionsEvent $event) {

          $event-&gt;linkOptions = [];
  }
);

Which removes all Craft links, but how do I remove the categories links only?
At the moment, your are overriding $event-&gt;linkOptions which contains an array with all options to an empty array with $event-&gt;linkOptions = [].
First, add the below to your module and refresh any page on your site so you see what you are working with:
Event::on(
  RedactorField::class,
  RedactorField::EVENT_REGISTER_LINK_OPTIONS,
  function(RegisterLinkOptionsEvent $event) {

    Craft::dd($event-&gt;linkOptions);
  }
);

In the array you saw above, you want to remove the object containing a 'elementType' =&gt; 'craft\\elements\\Category'.
You can do this by searching $event-&gt;linkOptions for craft\\elements\\Category, remove it but still returning the rest of the options.
Here's one way of doing so:
Event::on(
    \craft\redactor\Field::class,
    \craft\redactor\Field::EVENT_REGISTER_LINK_OPTIONS,
    function(\craft\Redactor\events\RegisterLinkOptionsEvent $event) {
        $defaultOptions = $event-&gt;linkOptions;

        // Search for category element
        $categoryLink = \craft\helpers\ArrayHelper::where($defaultOptions, 'elementType', 'craft\\elements\\Category');

        // If present, remove the option and return the rest
        $event-&gt;linkOptions = \craft\helpers\ArrayHelper::without($defaultOptions, key($categoryLink));
    }
);