I actually know of one, NOWPayments. I came to know about them while I was transacting on an online clothing store. The store had this WooCommerce plug-in that equips them to accept payment in litecoin and other cryptos with ease. I had to research on this payment gateway because I was wowed with how fast the transaction went and I do recommend them to merchants. You can read about them on their website https://NOWPayments.io