Missing options in the target dropdown for the general link’s internal link form? The options are sourced by the search index for some reason.

check if a simple reindex of your core index will do the trick

If you’ve already tried that and still no dice, you may run into the same issue i did. After going to Sitecore Support i got a few good pieces of information.

1. In order to use Azure search in Sitecore you need to limit the fields indexed by Sitecore. Typically done with <indexAllFields>false</indexAllFields>
2. There are some fields required by SPEAK to make these forms work properly

The Solution

There are a few templates and fields that need to be available for this functionality to work properly. Make sure your solution has these standard configuration nodes set up.

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:search="http://www.sitecore.net/xmlconfig/search/">
  <sitecore role:require="ContentManagement or ContentDelivery" search:require="azure">
    <contentSearch>
      <indexConfigurations>
        <defaultCloudIndexConfiguration>
          <documentOptions>
            <include hint="list:AddIncludedTemplate">
              <StandardTemplate>{1930BBEB-7805-471A-A3BE-4858AC7CF696}</StandardTemplate>
              <CommonText>{76F63DF7-0235-4164-86AB-84B5EC48CB2A}</CommonText>
            </include>
            <include hint="list:AddIncludedField">
              <fieldId>{8CDC337E-A112-42FB-BBB4-4143751E123F}</fieldId>
              <hidden>{39C4902E-9960-4469-AEEF-E878E9C8218F}</hidden>
            </include>
          </documentOptions>
        </defaultCloudIndexConfiguration>
      </indexConfigurations>
    </contentSearch>
  </sitecore>
</configuration>