Fast Charger & USB C to Lightning Cable
The iPhone X can fast charge with the right accessories. In the box you get a charger and a cable that charge at the same speed as the iPhone 7, but with a USB C to Lightning cable and the right power adapter you can charge the iPhone X battery 50% in 30 minutes.
You will want to buy the official Apple USB C to Lightning cable for $25. Don't buy knockoffs on Amazon as most we've found don't support the fast charging spec.
From there you need to a charger that can output at least 29W of power over USB and that supports USB PD. If you already own a MacBook or MacBook Pro with USB C, you can use that charger.
If you don't we recommend buying one of the best iPhone X fast chargers that will give you enough power for as little as $17.99 on Amazon.