Hi @Ramsey, Dwayne ,
In your case the site page content type listed in your test tenant, but not displayed in the admin content type gallery, you want to get it to appear.
Per my knowledge, you cannot get it to appear .If it is deleted, we cannot restore the content type. We don’t have an option to restore the deleted content type.
If you wish to apply to production tenants, you can only create a new one by selecting the Parent Category as Document Content Types in the admin content type gallery then publish .
Here are steps:
1.Sharepoint admin center->content services->content type gallery
2.Create content type->create
3.Click the content type name->publish
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