I absolutely love my 8Bitdo SN30 Pro+ for use with my pi (and also literally everything else I want to use a controller for). I feel like I'm shilling a bit right now, but go check out their site, they've got lots of great retro-style bluetooth controllers.

Otherwise, check out the controllers section of the RetroPie Docs. Here's the PS4 controller section since I can't link to the overall controllers section. Typically, you can connect any kind of bluetooth controller with no hassle, but this section shows how to connect many other controllers.

And if you end up really needing a wired controller and are worried about wire length, female-male usb cables (essentially usb extension cords) aren't exactly expensive.

8bitdo SN30Pro Plus with the official phone mount. I love mine

It also works great as a Switch Pro controller, be it on Switch or PC (it has both xInput and Pro Controller modes built in)

https://www.amazon.com/8Bitdo-Sn30-Pro-Bluetooth-Gamepad-mac/dp/B07T8JKVNT/

https://www.amazon.com/8Bitdo-Smartphone-Bluetooth-Gamepad-Black-pc/dp/B07VGHS48G

You can also get the Pro 2 (it has physical mode switch instead of a key combo) but I can't find a phone clip for it on Amazon

I bought this one. Works great. Build quality is superb. Has a turbo function per button. And saved me hours of frustration with other Bluetooth controllers.

8Bitdo Sn30 Pro+ Bluetooth Gamepad (Sn Edition) - Nintendo Switch https://smile.amazon.com/dp/B07T8JKVNT/ref=cm_sw_r_cp_api_i_FmuyFb2P7MK1J

General consensus is that most third party GCC are not worth it for competitive smash.

My experience with Cipon is that they look in photo but they feel like garbage. Especially if you already used or tired an OG controller. Bad sticks, funky shoulder and z button, oddly clicky face buttons, etc.

Sadly there isn't really any cheap AND good alternatives but here is a couple recommendations.

• Pro controller ($60) is your best bet if you're an ult player.
• 8bitdo sn30 pro + ($50), Although I've never tried it you could try it, it may be good if you are used to old ps controllers.
• PG GCC (priced unknown, probably ~<$70) Yet to be released so if you are patient is probably best third party GCC but it's not going to be cheap.
• frame1 (heavy $200 or light $120). If you are ok using fightpads it's a good option. Although they are a steep cost they it's a good price to quality for a fightpad. Currently out of stock but will restocked be end of Feb or start of Mar. There are others but I like Boxx or hitbox but frame1 is best IMO.
• Gloom DX mod (~$200), best GCC even better than OG but it's very expensive and only really worth it for extreme melee players.

[The 8bitdo SN30 Pro Plus is one of the best controllers I've ever used.](8Bitdo Sn30 Pro+ Bluetooth Gamepad (Sn Edition) - Nintendo Switch https://www.amazon.com/dp/B07T8JKVNT/ref=cm_sw_r_cp_apa_i_R2MKDbZ5PR9AN)

Works with Android and pretty much everything else.