I am also that husband who is hard to shop for, I have seen my wife go through what you are going through! I usually tell her, "don't get me anything at all... I already bought it for myself a month ago anyway."
A gift card is a 100% safe pick, but also kind of bland. You didn't need our help to come up with that. If he doesn't already have them, the TC Unitune and the Geddy Lee book both seem like great ideas. The tuner is tops for what it is, and the book is just cool.
If he hasn't seen the [Jaco Pastorius documentary yet](
https://smile.amazon.com/dp/B015NLGXA6/?tag=jacopasttheof-20&sa-no-redirect=1), he would probably enjoy it... any dedicated bass player would.
How about a
Plek job for his favorite bass? You don't have to ship it away... a luthier in your area may have Plek gear. It's a couple hundred bucks I think. Maybe you could coordinate with the shop so that you only have to sneak the bass out of the house for an afternoon.
Does he have a way to record what he is doing? Even if he is not trying to do professional recordings, listening to yourself practice is super helpful, so a way to record into your computer is a great tool.
Can you think of any area of bass playing that he is trying to improve? There are great instructional resources out there. Talking Bass has super courses for all skill levels and you buy the content and keep it forever. Scott's Bass Lessons is a yearly membership joint. SBL has a LOT of content and from what I saw, most of it is better suited for intermediate to advanced players, while Talking Bass also has content that is good for beginners (plus much better written course materials). There are several other places to buy instructional materials.
Can you think of any aspect of bass playing that he hasn't dabbled with yet? For example, maybe he has only fretted instruments ... a fretless would be a sweet addition. Maybe he only has standard scale instruments and would enjoy trying a short scale. Maybe he is the kind of person who has a mountain of amplifiers, cabinets, and pedals ... a modern multi-effects/modeler gizmo is a totally different way to work with your sound and some people LOVE it once they try it.
I have also seen a number of people around here say that one of the best things they did for their bass playing was learning to play drums. A small electric drum set would be enough to learn the basics.
Obviously, that stuff is more expensive than a book!
I know it is damn hard to pick the right thing for a picky person, but that becomes easier once you are looking into stuff that is a little off their usual course... and I think those makes the best gifts anyway. And I promise you, this forum will do a great job helping you pick out an instrument or anything else.
