Bally's Double Header is a bingo that isn't seen much and is considered hard to find.
https://bingo.cdyn.com/machines/bally/double_header/

valuable and rare don't really go together.

there's a few games that aren't seen for sale very often like Twist, Big Wheel, Magic Ring, some of the barrel-o-fun/lotta-fun games, Crosswords, Double Header, Broadway '51, Parade, Bounty and some of the early mystic line games like Follies Bergeres

while double header and bounty would tend to fetch higher prices, the other ones usually sell for less than average. They weren't popular in their day so didn't sell particularly well, therefore the number surviving is lower.

To me, the most valuable machines are the ones that work
Terry K

Hy brid complete (resized).JPG

Very hard to find bally double header and worth $ most screen games all.made by Bally. United SHOWBOAT Serenade and Rodeo Serenade being the most $ 345 the most rare

Bingos and "valuable" do not go together in my experience. Plus, they're SUPER HEAVY to move.

I saw a Lido sell on eBay for $1,600 several years ago. Nothing else I've seen sell on eBay has cracked $1,000, so vireland is spot on in his observation that bingos and big bucks aren't even in the same zip code. If you change the question from valuable to "desirable," I'd say Silver Sails or Golden Gate (with the Golden Game feature) or Lido or Bikini (with the Futurity feature). Those would be at the top of my desirability list.