I needed to remove several of the options from the product type dropdown in WooCommerce. This may not be the correct way to do it but it does hide them.
From This:

To This:

Code:
add_filter( 'product_type_selector', function( $types ) {
if( isset( $types['external'] ) ){
unset($types['external']);
}
if( isset( $types['variable'] ) ){
unset($types['variable']);
}
if( isset( $types['grouped'] ) ){
unset($types['grouped']);
}
if( isset( $types['simple'] ) ){
unset($types['simple']);
}
return $types;
} );