I’m looking for a cable to work with my wireless charger (15W metal fast charger) but would also like it to be somewhat future proof. I’m using a Powerport+ 6 which has a quick charge 2.0 port.
To get the best power output, does it matter if i get a USB C to USB A 2.0 cable, or do I need USB C to USB A 3.0. Its unlikely to be used for data transfer, just charging.
Most of my cables are Powerline+ and I would like to keep to this type if i can. OCD will kick in otherwise! 
For charging speeds, it doesn’t matter. Only difference you’ll notice is with data transfer.
In all fairness I have both 2.0 and 3.0 Anker cables and my phone shows fast charging only with the Usb-C to USB-A 3.0 cable
As has been said, there is no difference in charging performance between USB 2.0 and 3.0. The same is true with USB-C to USB-C cables.
If you want a USB-C to USB-A cable for everything, including data transfer, then get a USB 3.0 one. If it will only be used for charging various devices then get a cheaper USB 2.0.
If you want to future proof then get a USB-C charger and USB-C to USB-C cable. More new devices will be coming with USB-C. There is a power transfer limit within USB-A, so your current setup won’t support USB-C Power Delivery. And there will be no future innovations involving USB-A connectors.
Thanks for your replies.
I’m using these right now. They come in 3 foot or 6 foot lengths and are premium quality:
Good recommendation and the price is good