Web notifications, which highly trafficked sites web sites are using them? (A list of...)

I'm evaluating to add in my company's web site web push notifications and I want to study some "production" cases. I didn't find any important e-commerce, social network or simple web site that use web push (e.g Facebook, eBay, Amazon) Could you help me to find a list of highly trafficked sites that adopted web notifications?

Many thanks.