||Note this event is not in Sheffield, but could be of interest.
Sparrows' Nest Library and Archive has been operating since 2008 (like Alt-Sheff). It holds books, pamphlets, zines, leaflets, posters etc. focussing on the history of anarchist and social movements, protests and radicalism in Nottinghamshire, and the wider regions of East Midlands and South Yorkshire. They offer an online catalogue with downloadable copies, and visits by arrangement.
This event covers 50 years of Nottingham's rich tradition of radical publications. Note it is being held not at the archive, but in Notts Zine Library at Nottingham Contemporary, in the city centre. Free entry, accessible venue.