The 8Bitdo Sn30 Pro+ Bluetooth Controller is popular because it's supported by the Nintendo Switch. For smartphones, I recommend the Razer Kishi Mobile Game Controller because you can cradle your phone into it as if it were a Nintendo Switch.
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I know Bluetooth gamepads are all the rage, but I know some of you prefer a wired controller (they're far easier to set up). I recommend this gamepad: Logitech Gamepad F310 (it's not featured below because they don't allow product embedding). It's a nice, solid gamepad with a smooth grip and 11 buttons.
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