diff --git a/lib/class-wp-theme-json-gutenberg.php b/lib/class-wp-theme-json-gutenberg.php
index db311fd570108..e7b825aae54cf 100644
--- a/lib/class-wp-theme-json-gutenberg.php
+++ b/lib/class-wp-theme-json-gutenberg.php
@@ -606,9 +606,13 @@ public function __construct( $theme_json = array(), $origin = 'theme' ) {
 		$registry            = WP_Block_Type_Registry::get_instance();
 		$valid_block_names   = array_keys( $registry->get_all_registered() );
 		$valid_element_names = array_keys( static::ELEMENTS );
-		$valid_variations    = array(
-			'core/quote' => array( 'plain' ),
-		);
+		$valid_variations    = array();
+		foreach( self::get_blocks_metadata() as $block_name => $block_meta ) {
+			if ( ! isset( $block_meta['styleVariations'] ) ) {
+				continue;
+			}
+			$valid_variations[ $block_name ] = array_keys( $block_meta['styleVariations'] );
+		}
 		$theme_json          = static::sanitize( $this->theme_json, $valid_block_names, $valid_element_names, $valid_variations );
 		$this->theme_json    = static::maybe_opt_in_into_settings( $theme_json );
 
@@ -2833,6 +2837,12 @@ public static function remove_insecure_properties( $theme_json ) {
 		$valid_block_names   = array_keys( static::get_blocks_metadata() );
 		$valid_element_names = array_keys( static::ELEMENTS );
 		$valid_variations    = array();
+		foreach( self::get_blocks_metadata() as $block_name => $block_meta ) {
+			if ( ! isset( $block_meta['styleVariations'] ) ) {
+				continue;
+			}
+			$valid_variations[ $block_name ] = array_keys( $block_meta['styleVariations'] );
+		}
 
 		$theme_json = static::sanitize( $theme_json, $valid_block_names, $valid_element_names, $valid_variations );