interface Messenger
{
    public function sendMessage(string $recipient, string $message): void;
}

class SlackMessenger implements Messenger
{
    public function sendMessage(string $recipient, string $message): void
    {
        app(Slack::class)->send($recipient, $message);
    }
}

class TwilioMessenger implements Messenger
{
    public function sendMessage(string $recipient, string $message): void
    {
        app(Twilio::class)->sendSMS($recipient, $message);
    }
}

// AppServiceProvider::register()
App::tag([SlackMessenger::class, TwilioMessenger::class], Messenger::class);

// somewhere in your application
$messengers = app()->tagged(Messenger::class);
foreach ($messengers as $messenger) {
    $messenger->sendMessage($recipient, $message);
}