The Nintendo Switch Pro Controller is (by most accounts) the best gamepad available for the Nintendo Switch. It has a better fit than the Joycon mounting bracket included in the Switch's box, but with the same haptics as Joycons. The controller is almost always priced at $69.99, but right now it's available for $59.00 at Amazon.

This controller has a more standard shape and fit than the Joycon controllers that come with the Nintendo Switch. There's a USB Type-C port for charging (just like the Switch itself), two sets of trigger buttons, and the same haptics as the Joycons. The Pro Controller also has the an NFC sensor for Amiibo, in the rare event that you actually use Amiibo figures for their intended purpose (instead of just looking neat on a shelf).

This is the best controller available for the Nintendo Switch, and Amazon has it for $11 below the usual price.
Nintendo Switch Pro Controller

This is the best controller available for the Nintendo Switch, and Amazon has it for $11 below the usual price.

Even though the Pro Controller works best with the Nintendo Switch, most devices running Android 10 or later should be able to connect to it too. There are also various ways of using a Pro Controller with Windows PCs and Steam.