This is IT.
SET MINDS TO BLOWN: Here’s a brainmelting and substantial archive of International Times, the UK’s foremost underground periodical, offering beautiful per-page scans (and text versions, making the archive searchable) spanning three decades of psychedelic counterculture madness. And here’s an issue guide on the official IT site to help you dig up articles of interest, of which there are thousands.
See also my old post about The Realist archive if this somehow leaves you hungry for more.