Stuart McGill recommends periodically standing and stretching your arms over your head a couple times. You can see the motion demonstrated here: https://m.youtube.com/watch?v=bcbuhePZZj0&t=459s

He also recommended doing the cat-cow from yoga, and there's a set of exercises referred to as the McGill big 3.

I've seen some positive references to the McKenzie method book, Treat Your Own Back. I haven't tried it specifically, but had good luck with their equivalent book for neck treatment.

Basic yoga moves are fantastic for this.

Sun salutations with downward and upward dog. They also strengthen your core.

There are more moves in the Ashtanga sequence, whenever I do it I get a feeling of my discs being stretched and exercised like a rubber ball.

One of the best back stretches that I've found is hanging from a pull-up bar (wall-mounted, removable door frame bar, power rack).

The recent version of Stretching[0] also has computer-specific stretches in it. I was recommended this book by a physical therapist and it's great.

[0]https://www.goodreads.com/en/book/show/561546

Not the original commenter, but I've started doing basic piriformis stretches. Even just the first one on this list has noticeably helped my back/sciatica pain.

https://health.clevelandclinic.org/piriformis-syndrome-stret...

I've added it as a goal in the Finch app, so I get a little dopamine reward when I do it.

Plus owning a dog helps too, getting regular exercise even if it's just walking.