Just finished programming a solver (well, ripping apart someone else's solver) to solve for all the possible states (hint, look up Knuth's Algorithm X).
Don't imagine they'd ship in time though if you were interested.
LED controller so you can e.g. have mail notifications as an LED on your desk https://www.blinkstick.com/
A clock that you can reprogram to e.g. to kind of a drunken walk with the seconds hand and still be on time. https://www.tindie.com/products/nsayer/crazy-clock/
Logitech also makes some nice wireless mice around $100 that are pretty ergonomic and comfortable to use. Anything to help prevent carpel tunnel is nice.
A lot of programmers really love the jetbrains tool suite, but that's more subscription based.
A lot of free database viewer tools pale in comparison to their paid counterparts. So something in that arena could be nice
Desktop steam engines [1]
You can get the engine on its own which can be powered by a candle or small oil burner. Then you can build your own stuff to starch to it to be powered!
Etsy Link...err tindy
https://www.tindie.com/products/stephanelec/mooltipass-mini-...
But what programmer wouldn't want their own open source customizable authenticator?
Edit** I guess it is technically just a password vault but I think it is still a pretty cool gift. Another thing I think would make a nice gift is this (I must be on a password kick tonite)
Tindy Link
https://www.tindie.com/products/russtopia/psstm-mark-ii-pass...
I also have a book on linear algebra, which would be good for people doing more machine learning or data sciency stuff: https://www.amazon.com/dp/0992001021/noBSLA
Both books are perfect for math haters, since they start out with a review of high school math.