Here are some fun tools i've come across that I can't live without:
A blacklight for seeing dust on product photography sets. Also makes glow in the dark stuff REALLY glow (for funsies)
Remote triggers for your cameras. Works with Phase, Canon, Nikon, etc. Also works as an emergency flash trigger if needed. Seriously, these are the best, it improves my workflow and I've seen everyone from product to wedding photographers use these. Buy multiples.
Anti-static cloth. Usually sold as a cloth for cleaning film negatives, its great for product photographers.
Laptop Repair Kits are equal parts helpful for repairing electronics but also for styling tools.
A mouse built for hardcore gamers ...I know what you're thinking— a mouse? A MOUSE?? But it's seriously very helpful. Some video games utilize the number pad on your keyboard as 'hot keys' for quick functions. These mice (mouses?) are built to have that on your mouse. These kinds of video game mouses (mice?) are highly customizable and you can program 16+ different buttons on this model alone I believe. Pair it with A Better Touch Tool and a Better Snap Tool and you have a lethal combo for efficiency. I have mine set to quickly go forward / backwards on web pages, quickly full / half / quarter application windows, and I could set whole key commands for photoshop, Capture one, etc.
Additionally, Gaming keyboards are great too. Typing with a "Real" keyboard is a treat! Plus. they can feature the same 'hot keys' and programmable extra buttons. Want a series of 5 custom buttons that can execute your entire Photoshop script? Done. Also, they last a long time and are comfortable to use. Lets be clear: Apple mice (mouses?) and keyboards aren't good. They aren't, and never will be.
A phone stand for your desk its kind of nothing in the scope of things but....I really like having one around.
And as a final plug: USB Strip lights. It's great for adding lights to work stations or computers especially if you work late at night and want less eye strain. HOWEVER, keep in mind that you likely will have trouble finding one that is 100 percent color corrected. You're going to be guessing here. This may impair your color accuracy in photoshop or editing, however, I think most people don't have that setup in their daily workflow anyways so...you should be OK. Just be aware of that.