Most popular PC games today can't just be played with a keyboard and mouse. You need a gaming controller.

A good gaming controller’s buttons and triggers are responsive and smooth. Their shoulder buttons are snappy and easy to reach for hands of all sizes and index fingers of all lengths. 

Their direction pads (D-pads) have discrete inputs for each direction, giving you precise control in platformers and fighting games.

Good gaming controllers have analog sticks (also called thumbsticks or joysticks) , which are easy to reach and comfortable to grip with your thumbs,

Wireless controllers allow you to sit farther from your computer without having to wrestle with a cord. However, the wireless connections can cause your inputs to take longer to register in the game.

Some experts say that the best PC controllers are console controllers. 

The best PC gaming controller: Sony DualShock 4 Wireless Controller (Comfortable for most hands)

The second best PC gaming controller: Xbox One Controller + Wireless Adapter for Windows 10 (Easy to set up)

The best affordable PC gaming controller: Xbox 360 Controller for Windows (easy to set up)

The best fancy PC gaming controller: Xbox Elite (pricey, more customization options)