I bought a OBDLink Mx a long time ago and it has worked on every car i have had to diagnose. (Mercedes, Skoda, VW, SAAB, Porsche)

Veepeak and obdlink are good generic ones in my experience, BimmerLink even recommends a specific obdlink one for example, think it has an STN2120 rather than the usual ELM327 clone chips and thus is a bit higher quality, but for most cars and most apps, the ELM based ones work.

If you use or might one day want to use IOS, get one with BT LE support and connect via app, not the Bluetooth menu. If you do, you'll have to restart the phone to get it to show up again, stupid iOS thing.

I've had a couple of these (with different branding): https://ebay.io/m/UJMLDM

Despite the name they're not that durable, the first one I had rattled apart after a few years, but at that price idgaf. It's Bluetooth so you need to install a companion app. It's only obd2 though, it won't read any fancy proprietary make-specific codes.