My dad's mate called Dave he's a rag but a fellow blue he knew called Bernard died a good while back maybe a good few years ago and he was obsessed with a major collection of his own, he had an absolutely massive programme collection every home and away match possible for way over 60 years at the time and every major match in our complete history he could, he paid a lots of money obtaining everything he could and wanted every single programme according to Dave, Bernard also proclaimed to him he had the most "nobody has a bigger collection than me" whether that's true or not I don't know, Dave certainly believed him though and although many collectors are very humble I presume except to a select few friends like in this instance Bernard was confident of that, for the rarest ones Bernard paid big money for them some a good chunk are even reserve team and youth team matches whenever possible because it was his passion.
Dave told me one of Bernard's quirkier possessions is a super rare Manchester derby programme he obtained on the day with a difference, they played a Cricket match at Lancashire Cricket Ground I think either in the late 60s or early 70s featuring all the stars of both teams at the time golden eras I've heard and it was a single sheet programme preserved in very good condition, maybe
@Gary James would know more about the actual game that was played I don't know anything about the innings and outs of it, apparently as far as match memorabilia goes it's one of the most rare or certainly more quirky ones to find in good condition without natural wear and tear as it was a novelty event.
I'm not exactly sure what happened to Bernard's absolutely massive collection, probably not too dissimilar to your own newly obtained collection I imagine but Dave reckoned City should've defo been looking at Bernard's, in a sense maybe they should be looking at yours for some of the more rare matches at least... Dave even as a rag says it was the most amazing collection he'd ever seen.
I just hope somebody is preserving them all somewhere in the best possible condition as it's all part of our wonderful history, as the years go by most will become very weathered and degrade over time if not properly kept in a good environment.