problems with USB C lately doesn't exactly makes you confident to use any cable other than the ones which came with the device.
But before you throw away your old MicroUSB cables (which can be expensive if you bought good quality ones), there might be something you can do about.
The Choetech MicroUSB -> USB C adapter is the inexpensive and working solution for the Google Pixel / Pixel XL to reuse your old MicroUSB cables.
It is important that you check what cable your device needs. For the Pixel/Pixel XL, Lumia 950, Lumia 950 XL, Nokia N1, Lenovo Zuk Z1, Nexus 5X, Nexus 6P, HTC 10, LG G5 & Pixel C and many other USB Type C devices, this is the right one.
The 56k Ohm resistor makes it a safe experience in terms of charging. Since there are rarely powerbanks with USB C connector, this is very handy in many ways.
In terms of data transfer it makes up to 480mbit/sec.
So if you're unsure about if it can harm your precious device, you can take a look at this. I already tested it with the Pixel XL on a normal charger (1.4 A and 2.4 A).
There are 2 adapters in the package, to recycle 2 old cables for your new device.