I use these: https://www.amazon.com/Brown-Smooth-Leather-Full-Pack/dp/B073H9RQ55/ref=zg_bs_10342495011_86?_encoding=UTF8&psc=1&refRID=BJ5M10PGR5S62ABFKMSA
Amazon has about a billion and one cases to take a look through, but the classic clamshell with faux leather hasn't steered me wrong for years now.