One rarely quoted alternative is the reward Reward Flight Finder on the BA App. One of the advantages over rewardflightfinder.com is that you're able to see all the cities in one go. Click on the hamburger in the BA App and select Reward Flights. Touch Go under Reward Flight Finder and put in your search criteria (e.g. From London to North America, the month in question and your preferred cabin). Touch Find Flights and see the cities with availability.