Teng here and like them a great deal:
https://www.amazon.co.uk/dp/B000Y8HLNC
…and they also do a similar Torx set:
https://www.amazon.co.uk/dp/B000Y8HLPK
These are my primary go-to allen keys and I’ve found them excellent. You can also buy them individually when they start to go tired, but so far, I’ve not needed to.
Oh, one other daft thing, but I have a set of machined small allen keys which are a hold over from my days racing RC cars. I’ve never come across anything like them in mainstream sets as the edges of the hex are literally razor sharp and for tiny adjusters (e.g. brake reach etc) they are absolutely second to none. They are a much valued tool and kept in a safe place so they don’t get beaten up in the toolbox!
These are the closest I can find:
https://www.modelsport.co.uk/arrowmax-allen-wrenches-1.5-2.0-2.5-3.0-4.0-5.0x120mm-6-pcs/rc-car-products/40246
They aren’t exactly like mine, but they are machined so I assume they would be similar. Highly recommended, but not cheap 🙂