Filter: bricks/elements/{element_name}/controls

Since Bricks 1.3.2 it is possible to add custom controls to any element like so:

add_filter( 'bricks/elements/posts/controls', function( $controls ) {
    $controls['ignoreStickyPosts'] = [
        'tab'      => 'content',
        'group'    => 'query',
        'label'    => esc_html__( 'Ignore Sticky Posts', 'my_plugin' ),
        'type'     => 'checkbox'
    ];

    return $controls;
} );

Note: the above example adds a new checkbox to the posts element, using the filter bricks/elements/posts/controls. To learn about other Bricks controls visit the Topic: Controls.

You might also be interested in the filter bricks/posts/query_vars to manipulate the posts element query.