deny-list-bock.js

wp.domReady( function() {

    //wp.blocks.getBlockTypes().forEach( function( blockType ){ console.log( blockType.name ); });

    var core_variations = [
        'core/archives',
        'core/audio',
        'core/avatar',
        'core/block',
        'core/block',
        'core/button',
        'core/buttons',
        'core/calendar',
        'core/categories',
        'core/code',
        'core/column',
        'core/columns',
        'core/comments',
        'core/cover',
        'core/file',
        'core/freeform',
        'core/gallery',
        'core/group',
        'core/heading',
        'core/html',
        'core/image',
        'core/latest-comments',
        'core/latest-posts',
        'core/list',
        'core/loginout',
        'core/media-text',
        'core/missing',
        'core/more',
        'core/navigation',
        'core/navigation',
        'core/nextpage',
        'core/nextpage',
        'core/page-list',
        'core/page-list',
        'core/paragraph',
        'core/post-author',
        'core/post-author-biography',
        'core/post-comments-form',
        'core/post-content',
        'core/post-date',
        'core/post-excerpt',
        'core/post-featured-image',
        'core/post-title',
        'core/preformatted',
        'core/pullquote',
        'core/query',
        'core/query-no-results',
        'core/query-pagination',
        'core/query-pagination-next',
        'core/query-pagination-numbers',
        'core/query-pagination-previous',
        'core/query-title',
        'core/quote',
        'core/read-more',
        'core/rss',
        'core/search',
        'core/separator',
        'core/shortcode',
        'core/site-logo',
        'core/site-tagline',
        'core/site-title',
        'core/social-link',
        'core/social-links',
        'core/spacer',
        'core/table',
        'core/tag-cloud',
        'core/term-description',
        'core/text-columns',
        'core/verse',
        'core/video',
        'happyfiles/gallery',
    ];

    var embed_variations = [
        'amazon-kindle',
        'animoto',
        'cloudup',
        'collegehumor',
        'crowdsignal',
        'dailymotion',
        'facebook',
        'flickr',
        'imgur',
        'instagram',
        'issuu',
        'kickstarter',
        'meetup-com',
        'mixcloud',
        'pocketcasts',
        'reddit',
        'reverbnation',
        'screencast',
        'scribd',
        'slideshare',
        'smugmug',
        'soundcloud',
        'speaker-deck',
        'spotify',
        'ted',
        'tiktok',
        'tumblr',
        'twitter',
        'videopress',
        'vimeo',
        'wordpress',
        'wordpress-tv',
        'youtube',
    ];

    for (var i = core_variations.length - 1; i >= 0; i--) {
        wp.blocks.unregisterBlockType(core_variations[i]);
    }
    for (var i = embed_variations.length - 1; i >= 0; i--) {
        wp.blocks.unregisterBlockVariation('core/embed', embed_variations[i]);
    }
} );

I just discovered that 'core/list' needs 'core/list-item' to work properly, although 'core/list-item' is not printed in the list

Given they're likely to modify the core/embed variations -- adding and removing over time -- rather than enumerating all the variations, you can call wp.blocks.getBlockVariations('core/embed') which will return an array of variation objects. Then you can use the name property to unregister each:

  wp.blocks.getBlockVariations('core/embed').forEach(function (embed_type) {
      wp.blocks.unregisterBlockVariation('core/embed', embed_type.name);
  });

If you want to allow particular variations then just wrap a conditional around the unregisterBlockVariation call using the embed_type.name.