Inateck has their own USB Type-A to Type-C cable on sale right now over on Amazon. It's coming in at $6.99 with the promo code FKD6GWAY. This cable will work with your Nexus 5X and Nexus 6P without damaging the device, something that's going to be pretty important to everyone looking to buy a USB Type-C cable these days. Benson Leung, the Google engineer reviewing these cables did review their older one. It had a few issues, which have been fixed in this newer version that is on sale today. The USB Type-A connector is compatible with USB 1.0, USB 2.0 and USB 3.0 as you'd expect. No word on how long the cable is, but it's likely 6.6-feet as is normal with these cables right now.
This cable from Inateck will work with the Apple Macbook 12-inch as well as the Pixel C and the Chromebook Pixel (2015 models). So those with those devices or the OnePlus 2, ZUK Z1, or Meizu Pro 5 can pick up this cable and not have to worry about having any issues with the cable damaging your devices as it does output the proper power. This cable is compatible with Quick Charge 3.0, although you'll need a Quick Charge 3.0 wall adapter to work along with it.