I see. Then I could suggest you to do all of your reading(assuming your job requires reading) while standing or wandering around in your cubicle. Not only when reading though, you can stand whenever you can. For a 175 lbs adult, it can make a difference up to 50-60 calories per hour. That means, you can spend extra 75+ calories only by standing 10 mins per hour during a typical 8 hours of office work. Pacing up and down adds to it considerably.
Another thing I'd suggest, something I've done a lot in my library and at my desk at home, using a cute, small dumbbell. Only a one not a pair. A water bottle could also work but they are just too light for their sizes. You can stash it under your desk or in your closet etc and every now and then workout little routines with your non-busy hand and alternate. At first it may be distracting you from your focus but it quickly becomes autonomic and you don't even realize that you are working out. Plus it gives a pretty sweet toning to your arms before you know and you don't sweat at all while doing it.
Another thing is fidgeting. I remember reading that fidgeting your feet or hands can burn extra 250+ calories throughout a day. Pretty worthwhile to me, though I don't know how one can make it as a habit, if they don't have it.
Anyway, I know you're an avid googler but, I found this kinda funny link that has some office exercises. Some are silly, some sweaty but the graphics rate them on three levels about it. It's basic movements but might be worth to check out.
https://www.washingtonpost.com/wp-srv/special/health/workout-at-work/
Edit: Another idea might be adding to your body weight by using ankle weights. Though they are not recommended much by the physiotherapists and might not be convenient or easy to get used to.