Researchers of Newcastle's past may not at first be aware of the local history holdings (and various other general historical stuff) to be found at Newcastle University Library's 'Special Collections & Archives' department.
It's many years since I last visited the same, but was prompted to examine the matter when I saw the institution's 'Digital Showcase' pop up on Twitter/X. Do click on the link and have a gander - and it's sure to expand in the months and years ahead.
You can also access the page in question via the archive service's homepage - where you can also find links to other helpful bits and bobs, including the 'Explore Our Collections' guide. You will also see a that there is a blog to be accessed, too, which features a fair few interesting articles on the city's past.
There's probably a good deal more, too, that I've missed, so do put aside an hour or two to have a browse.
If you get the urge to actually visit the Library, then please check out the guidance on how to do so as a member of the general public. It is possible to visit to consult their holdings, but you'll need to get yourself a pass first.
Happy browsing!
P.S. Oh, and their YouTube Channel can be found here.