Internet is replete with reports of problems of USB Type C accessories. Also reported here, Can a faulty Micro-USB cable cause damage to your device?
How do I go about selecting right cable or charger, assuming I have a Pixel?
Note: This is a self answered question drawing from the spadework in answering a different question and felt it may be useful to share, given Type C is gaining popularity. Additional answers are of of course welcome! Guidelines in answer are not restricted to Pixel.
USB C Chargers/ Cables are a minefield - In implementation
The standards (as they should) are said to clear and consistent but implementation has been shoddy causing multiple problems and even burnouts. One Plus pioneered Type C on Android (One Plus Two) and set a wrong precedent by saving few cents, maybe, with a non- standard resistor . They are not the only ones, Apple and Google too , to an extent ( not to forget laptops )
Coming to Google, sample this, quoted from reddit post Please ELI5:Chargers, charging cables, and safety for my Pixel
where Nathan K , says :
USB-IF Certification testing costs money -- lots of money. $10,000 per product. So a lot of generic manufacturers simply do not do it. Instead, they make products by the seat-of-their-pants. Others, like Apple and Google say "Screw the USB-IF, we know better than them. We can self-certify." So products you buy in an Apple Store or from Google may not have a USB-IF logo, but are (mostly) good. (There are some exceptions I've discovered, noted in my list.)
(Emphasis supplied)
...Google sells people on buying a $35 USB-PD charger its own product doesn't even utilize. The only time it would be used is with expensive peripherals like charge-through hubs.
( I am not sure what exactly is not utilized, haven't researched further )
So, whom to trust ?
Nathan K is an independent tester, not affiliated to anyone (Google Plus ). Benson Leung is a Google software engineer ( Google Plus ). Individually and collectively, they carry out tests of practically any USB Type C equipment , chargers and cables and publish them on Google Plus.
They are doing a yeoman service by advising users on choosing right USB Type C accessories and their testing has at times forced prominent brands to remove products from sale (Anker, for example, see their blogs for more examples
Browse their blogs for the right accessory for your device and you may reach out to them on reddit / Google Plus
For Pixel users
You have it on a platter ! Nathan and Benson together they have curated a list of accessories that are tested for your device (details here ). Consider buying charger and cable based on the recommendations linked above (make sure look at the column titled "IR Drop compensation" (should have that). That is a very important feature to correctly charge
You will notice that some negatively or low rated accessories include OEMs like LG, google and Huawei !
Disclaimer: Haven't owned any device with Type C charging and nor I am affiliated anyway with Nathan or Benson
Additional Information
USB Type C over Power Delivery (PD) , is different from Qualcomm Quick Charging. Qualcomm's Quick Charge will not work on a Pixel. The charger will default to a spec-standard current and voltage
Can Qualcomm QC and USB Type-C coexist on the same connector?- No. Type C specs forbid that (though you will find cables that claim to do this on market- avoid them like plague). For the same reason, Nexus 6P and 5X do not support QC
USB-PD can only work with a C-C USB cables. A to C cables - (pic here ) cannot charge as per specs (max current possible is 1.5 A)
Q & A