Used second monitor and external keyboard recommendations?

I’m running rhino on an asus rog i7 w gtx 965m video card. It runs beautifully but with the 12 hours a day I’m modelling, I realized that I need a second monitor as the 17" laptop screen gets a bit tight with the layers windows. Can someone tell me what I should look for when buying a second monitor? I’m going to go used most likely to reduce costs. Thank you.

Also, if you have a usb or wireless keyboard recommendation, please suggest. Thank you twice!! :slight_smile: