University and community archives both are doing so much important work in curating and preserving queer history! And even the academic collections are generally still open to the public, whether that looks like you coming into the reading room at a local university to look at their materials or emailing the librarians to ask for photos or scans of them.
Also, like, even if they're affiliated with institutions, queer archives at universities and museums are generally still curated and cared for by queer folks. I work in a queer history archive at my university, and all of us who regularly work with the collections are queer, the curator is even another trans person, and we have strong connections with other queer people and organizations in the surrounding community.
Academic and cultural institutions like historical societies, libraries, and universities have facilities built to preserve archival materials -- everything from books and zines to pins, banners, t-shirts, and etc -- and people trained in curation and conservation. And often we want to connect with the local community so we can house and preserve their stories and materials for a long time!
All the archives that have been added to this post are great, but here's a few more to look at if you're interested in finding a queer archive near you -- or one further away with materials that interest you.
Australia:
The Australian Queer Archives
Canada:
The ArQuives (formerly the Canadian Lesbian & Gay Archives)
Also -- I know what's happening today is incredibly scary, but there are so many archives all over the world documenting our history, and so many people devoting their lives to preserving everything from groundbreaking political manifestos to kitschy ephemera. And supporting queer archives is more important than ever. My first day of work in the collections, the curator handed me a charred book that had been rescued from the Institut für Sexualwissenschaft book burnings, and nothing has ever driven home more that the work of archivists is both critical and powerful, especially in this day and age. Support queer archivists and queer archives, save materials and find one to house your own collections no matter how random they might seem, and go out and learn about our history!