Doesn’t have a shit QC (8bitdo’s are apparently like that)

Can't confirm. I own 3 controllers, a keyboard, a numpad and a mouse by 8bitdo. None of them have any hardware issues. Only issue is that the software is meh and Windows/Mac-only. But it's a plug-and-play controller, so you really don't need the software unless you want to do stuff like define macros (which you can just use Steam input for).

I've owned 3 different 8bitdos, and they have some of the best QC on the market.

With that, the ultimate 2 is a brilliant wireless 2.4g controller with a dock. Works out of the box, no config required.

Yeah 8bitdo is good in my experience, you can return it anyway if it's sussy on arrival. Works with everything, steam input or not

I own a couple of 8bitdo Ultimate 2, they're excellent and seem to tick all the boxes, but they're on the smaller end I guess.

Really? My 8bitdo outlived any other controllers I have owned, minus some features lacking

I just got a 8bitdo ultimate 2c they go for 30 bucks and I swear it is better than my Xbox gamepad, thy come in fun colors have extra triggers amazing hall effect sticks good face buttons. Bluetooth AND dongle. I can't stress this enough it is purple.

8bitdo, no other better answer

I'd save up +30€ and wait for the steam controller to be available

The 8BitDo Ultimate Wireless 2 has been perfect for me and fits all your criteria.
I know they had QC issues with their dpads on their earlier controllers but it seems they've long fixed that as I don't see people reporting it anymore on their subreddit.

I have a ton of 8bitdo stuff and have never had any issues. They're my favorite controllers.

My PS5 controller works perfectly on mint DE.

I really like the ps5 dualsense controller and had no issues whatsoever in Linux. Works really well. I'd even say better than in windows.

I use a Dualsense controller and it's great. It feels as responsive on my desktop as it does on a real PS5.

Though I mostly use it to play old Pokémon games through emulators and occasionally Bloodstained

I have a Gulikit KK3 Pro (NS38) and a KK2T (NS09), both are great and while I got them for free in giveaways, they go around 40€.

The KK2T is Bluetooth only, the KK3 Pro came with a dedicated 2.4GHz dongle (but Bluetooth is available as well)

Both have the Xbox stick layout, but the button layout is Nintendo (they are also switch compatible). Apparently, the buttons can be replaced, but I couldn't find a place that has the Xbox button layout in stock - at least not in my specific colorways.

The KK2T is plain black without any LEDs, the KK3 Pro I got is DMG Gameboy themed: Beige plastic, pink buttons and LED rings around the sticks that have different lighting modes (reactive to stick movement, solid, reacting to trigger pulls etc.)

Just an xbox controller?

It just works

Strong recommendation for Cyclone 2. I've been so happy with my first one that I'm about to order a second one.

Excellent ergonomics. The RGB you asked for. Works perfectly with my CachyOS and Bazzite setups out of the box. Premium metal charging stand included. Excellent clicky switches including changing triggers to micro switches. Hall effect triggers. TMR sticks. 2 back buttons.

This is available brand new on eBay for £30 in UK. You won't be disappointed.

I have 4 8bitdo Ultimate 2C gamepads. 2 Nintendo layout and 2 Xbox layout. They feel better than the Series X standard gamepad I had before. My oldest is 2 years old. Durable for me but I don't smash the buttons and sticks anywhere near as hard as possible like I've seen other people do when gaming. Like video game road ragers

8BitDo work well with my Steam Deck

I'm still a huge fan if my DualShock 4. I've been using it for a long time now, and the battery life is still good. The track pad also comes in handy shockingly often since it acts like a normal track pad for the mouse.

Throwing a fun one in comments:

Stadia Controller.

if you want an alternative to the List, I have had really good experience with the Anbernic RG pro. I had a little bit of a problem getting started with it, but after you update the firmware for the controller it’s been working perfectly for me and is a outstanding controller for the price.

I seem to have minor compatibility issues with most controllers on my EndeavourOS PC, but it seems to vary more with the games than with the different controller brands themselves. Seconding 8BitDo being pretty tough though.

Now the real question is, has anyone designed an open source controller (not fightstick/hitbox), that is purchasable? Like Ploopy or Tindie or something?

I have larger hands and have the Cyclone 2. Fantastic controller and my daily driver. I didn't like the clicky face buttons but they've grown on me. Happy to answer any questions. No real issues across Linux or Windows.

I have the GameSir Cyclone 2 and love it.

I have the GameSir Cyclone 2. The first thing I would say about it is that it's rather clicky. The buttons, the d-pad, and the hair triggers are all quite clicky. The sticks feel pretty great to me. I've had no issues with connecting it to a linux PC, and the 2.4 ghz dongle is a nice touch. Finally the only issue that you might run into is that the d-pad is a bit on the smaller side imo, although that might only come up for you if you play older style top-down JRPGs. Also as a side note I haven't had significant QC issues with 8 bit do and I have 4 controllers from them.