What can you give a radio amateur, not a beginner?

Question

Arduino

Tell me what you can give a radio amateur? He has an Arduino, a Raspberry pi (sort of). I would like to make a useful gift, something more complicated or something, not for a beginner. I don’t understand this well, but I want to please a person, so I turn to you)

Answer 1

I'm in favor of choosing a gift from what you understand. Otherwise, you will not be able to understand whether he has such a thing, whether he needs such a thing, is it better or worse than what he already has.
But if you insist, then for any man who does something with his hands, a good gift is a quality tool. Soldering iron / soldering station, hand tools (tweezers, screwdrivers), measuring tool (the range of price and coolness is huge!) - multimeter, oscilloscope. Etc.

Answer 2

I'm bad at this

That's it, then stop, you should not give anything related to his hobby, in 99.99999% of cases you will look stupid. Here, no one knows this person and cannot advise you anything, everyone will advise what they want.
At first I myself wanted to advise a good 3D printer, any do-it-yourselfer would be happy with such a gift, but then I thought that: 1. Maybe he already has one; 2. Giving bullshit for $400-600 is not a thankful thing, but you obviously do not count on $1000-1500; 3. You yourself do not understand this, so you can fly into the money without any problems.
The main thing you must understand is that a radio amateur is the same person as you and he has the same needs as you.

Answer 3

Banggood has interesting homemade gifts if you search for the word DIY there.