Another that I can't recommend enough is listening to old video game music. Something you love and played as a kid. For me it's N64: Zelda, Mario Kart, SM64, Banjo Kazooie. It's all on Youtube. There's something Pavlovian about music that accompanies passive focus and puzzle-solving.
Amiga games. Can't go wrong.
Also "pink" noise works rather well for me in extreme situations. I can even sleep in busy airports with it.
I.e. Sleep https://www.youtube.com/watch?v=hIw7oeZKpZc
Long answer: If you really feel this strongly about your working environment then you should seriously consider telling your manager. It's in their best interests that you're happy/comfortable/working as smoothly as you can. If they can't or won't change your situation, look for another employer. Ten years, Christ.
Actually I've had 3 over the past ten years. They're all the same. You've never noticed?
* work from home
* rent a private room in a co-working space
Use passive insulation, either in high quality headphones or ear defenders (much cheaper, but no music).
i mean come on.
o.p. has had three different employers in 10 years (and actually this goes back more like 15 years, since "open offices" became a fad, and five different employers). Every place is exactly the same.
source: am o.p.
That's why you have fewer guards in that system.
It breaks down when folks stop getting 'caught'.
But for my part, I don't know how you'd work under those conditions. I have a hard enough time working from home with my wife on the other side of the house teaching kids violin. I have both over the ear headphones and IEMs, though... that might help?
Here is what it comes down to: you can put a dollar figure on the money saved from going with an open office plan. You can't easily put a dollar figure on lost productivity due to conversations going on around you.